copepods and such

Dear mermaid:

Yes, seahorses can normally tolerate malachite green at the usual therapeutic doses, and Nitrofuracin Green is a good medication for seahorses with skin problems or mild bacterial infections (your seahorses with the "flakies" probably fall in that category). The Nitrofuracin Green also has some antiprotozoal properties, which can be helpful when treating protozoan parasites, as indicated below:

Nitrofuracin Green

A special formula of two nitrofuran antibiotics (nitrofurazone and furazolidone) + methylene blue and sodium chloride.

USE: anti-microbial, anti-protozoan, antibacterial, and anti-fungal. Wide spectrum. Good for newly arrived fish in quarantine situations. Also be good for healing wounds and ammonia burns on newly arriving fish. Widely used for shipping or packing water. Works well for sores on fish in Koi ponds.

DOSAGE: add 1/4 teaspoon per 20 gallons every 24 hours, with a 25% water change before each daily treatment. Treat for 10 days.

If those are the medication available to you, mermaid, I would set up a hospital tank with freshly mixed saltwater, give your seahorses a quick freshwater dip to provide them with quick relief from the ectoparasites, and then treat them in your hospital tank with the Nitrofuracin Green for 10 days while you are eradicating the mini jellyfish (the mobile medusa stage of hydroids) with the nasty stings from your seahorses take. The Nitrofuracin Green is a better choice than malachite green for seahorses with the "flakies," as you describe it.

Here are the instructions for performing a freshwater dip.

Freshwater Dips

A freshwater dip is simply immersing your seahorse in pure, detoxified freshwater that’s been preadjusted to the same temp and pH as the water the seahorse is accustomed to, for a period of at least 10 minutes (Giwojna, Dec. 2003). It doesn’t harm them — seahorses typically tolerate freshwater dips exceptionally well and a 10-minute dip should be perfectly safe. Freshwater dips are effective because marine fish tolerate the immersion in freshwater far better than the external parasites they play host to; the change in osmotic pressure kills or incapacitates such microorganisms within 7-8 minutes (Giwojna, Dec. 2003). A minimum dip, if the fish seems to be doing fine, is therefore 8 minutes. Include some sort of hitching post in the dipping container and shoot for the full 10 minutes with your seahorses (Giwojna, Dec. 2003).

If you will be using tap water for the freshwater dip, be sure to dechlorinate it beforehand. This can be accomplished usually one of the commercial dechlorinators, which typically include sodium thiosulfate and perhaps a chloramine remover as well, or by aerating the tap water for at least 24 hours to dissipate the chlorine (Giwojna, Dec. 2003).

If you dechlorinate the dip water with a sodium thiosulfate product, be sure to use an airstone to aerate it for at least one hour before administering the dip. This is because the sodium thiosulfate depletes the water of oxygen and the dip water must therefore be oxygenated before its suitable for your seahorse(s). Regardless of how you detoxify the freshwater for the dip, it’s important to aerate the water in the dipping container well beforehand to increase the level of dissolved oxygen in the water. Many hobbyists leave the airstone in the dipping container throughout the procedure.

Adjusting the pH of the water in the dipping container so that it matches the pH of the water in the aquarium is a crucial step. Ordinary baking soda (sodium bicarbonate) will suffice for raising the pH of the water. If there is too much of a difference in the pH, there is a possibility the seahorse could go into shock during the dipping procedure. Preadjusting the pH will prevent that from happening. If you will are unsure about your ability to accurately adjust the pH in the dipping container, avoid this procedure altogether or be prepared to monitor the seahorse very carefully or shorten the duration of the tip to no more than about 4 minutes.

Observe the horse closely during the dip. You may see some immediate signs of distress or shock. Sometimes the horse will immediately lie on its side on the bottom. That’s a fairly common reaction — normal and to be expected, rather than a cause for concern, so don’t be alarmed if this happens. Just nudge or tap the seahorse gently with your finger if it lies down on its side. Normally, the seahorse will respond to the slight nudge by righting itself again and calm down for the duration of the dip. However, if it does not respond, stop the treatment.

Most seahorses tolerate the treatment well and experience no problems, but if you see continued signs of distress — twitching, thrashing around etc. — stop the treatment.

After you have completed the dip and returned the seahorses to the aquarium, save the dip water and examine it closely for any sign of parasites. The change in osmotic pressure from saltwater to freshwater will cause ectoparasites to lyse (i.e., swell and burst) or drop off their host after 7-10 minutes, and they will be left behind in the dipping water. Protozoan parasites are microscopic and won’t be visible to the naked eye, but some of the other ectoparasites can be clearly seen. For example, monogenetic trematodes will appear as opaque sesame seeds drifting in the water (Giwojna, Aug. 2003) and nematodes may be visible as tiny hairlike worms 1/16-3/16 of an inch long. Other parasites may appear as tiny dots in the water. Freshwater dips can thus often provide affected seahorses with some immediate relief by ridding them of these irritating pests and can also aid their breathing by flushing out gill parasites.

If you suspect a problem with parasites, the dip should be extended for the full 8-10 minutes if possible for best results.

Here are some suggestions for setting up a makeshift hospital tank, mermaid:

Basic Hospital Tank set up

A bare-bottomed aquarium with plenty of hitching posts will suffice for a hospital ward or Quarantine Tank (QT). Ideally, the hospital tank should have one or more foam filters for biofiltration along with a small external filter, which can easily be removed from the tank during treatment but which can hold activated carbon or polyfilter pads when it’s time to pull the meds out. It’s important for the hospital ward to include enough hitching posts so that the seahorse won’t feel vulnerable or exposed during treatment. Aquarium safe, inert plastic plants or homemade hitching posts fashioned from polypropylene rope or twine that has been unraveled and anchored at one end are excellent for a hospital tank. No aquarium reflector is necessary. Ambient room light will suffice. (Bright lights can breakdown and inactivate certain medications and seahorses are more comfortable and feel more secure under relatively dim lighting.)

So just a bare tank with hitching posts is all you need for your hospital ward. No heater. No reflector. No lights. No substrate. You can even do without the sponge filters or external filter in your case, just adding a couple of airstones to provide surface agitation and oxygenation. That’s it.

In a pinch, a clean 5-gallon plastic bucket (new and unused, NOT an old scrub bucket!) can serve as a makeshift hospital tank. It should be aerated and equipped with hitching posts and perhaps a heater, but nothing else. This makes a useful substitute when the Quarantine Tank is occupied or in use and a seahorse needs treatment.

Stay on top of water quality in the hospital tank/bucket with water changes as often as needed during treatment, and and when you are treating the occupants for a health problem, re-dose with the medication(s) according to directions after each water change

Best of luck eradicating the mini jellyfish and treating your seahorses for the flakies, mermaid!

Respectfully,
Pete Giwojna

Dear mermaid:

Yes, you are quite right to be concerned about the translucent creatures with the white centers and white appendages. They are indeed a hydrozoans, the mobile medusa stage of a hydroid, which resemble tiny jellyfish. The problem is that they sting just like jellyfish too, and if your seahorses are trying to eat them, mistaking them for copepods or other tasty tidbits, they are a danger to your ponies. The seahorses are not at risk only when they snik up these micro-jellyfish, mermaid — they will also be stung anytime they brushed up against them are come in contact with one of the medusae micro-jellyfish. They are bad and you’ll need to eradicate them from your seahorses take.

Ordinarily, hydroids are only a problem for newborn and juvenile seahorses but any time your seahorses accidentally ingest one of the medusae they are in danger of suffering a serious injury.. And the irritation from a serious hydride infestation would certainly be a source of stress for the ponies, which could make them susceptible to bacterial infections and other problems.

As you know, mermaid, hydroids are always a concern for dwarf seahorse setups as well as nursery and rearing tanks that are receiving regular feedings of Artemia nauplii, rotifers, or copepods. Sooner or later hydroids will appear in any marine aquarium that is receiving regular feedings of rotifers, copepods, or baby brine shrimp. It’s inevitable because they can gain entry into the aquarium in many ways. For example, they are extremely accomplished hitchhikers. Both the colonial polyp stage and the free-swimming micro-jellies can thumb a ride on live rock, macroalgae, hitching posts, sand or gravel, specimens of all kinds, or within so much as a single drop of natural seawater (Abbott, 2003). Beware of fuzzy looking seashells! Very often hydrozoans come in on the shells of the hermit crabs or snails we purchase as aquarium janitors (Abbott, 2003). Or they may be introduced with live foods, or even among Artemia cysts, in some cases it seems. They can even be transferred from tank to tank in the aerosol mist arising from an airstone or the bubble stream of a protein skimmer.

It can be very challenging to identify hydroids because there are about a zillion different species of hydrozoans and the different types have different characteristics and are often vary remarkably in appearance. There is considerable variation within the species as well, and the same type of hydroids can appear vastly different depending on the size of the colony and its stage of development, conditions in the aquarium, and their predominant diet. And, of course, the different stages of the life cycle of these amazing animals are so entirely different that they were long believed to be different types of cnidarians altogether, and different species names were often assigned to the same hydroid in different phases of its life cycle. Because they are so difficult to identify and are not easy to distinguished with the naked eye during their initial stages, hydroids often go undetected in nursery and rearing tanks until they begin to take a toll on the fry.

The typical hydroid colony has a stem with a variable number of polyps growing on it, and each of these polyps bears numerous tentacles that are liberally studded with knobby nematocysts (batteries of deadly stinging cells). There are many different kinds of hydroids and they appear in the aquarium in many different guises: many colonies are stalked; some have fingerlike projections, others look like tiny pink fuzzy balls or appear like cobwebs (the webbing kind usually spread along the bottom or grow on the aquarium glass along the substrate). The "snowflake" type of hydroids seem to be particularly common in aquaria, whereas other species look more like crystal chandeliers, and some species form bushy colonies as they grow that serve as microhabitats for Caprellid skeleton shrimp and other tiny crustaceans.

Even a large hydroid colony appears harmless to the naked eye of the untrained observer. It takes a much closer look to reveal the dreaded ‘droid’s lethal nature, as described below:

"Studying the colony under high magnification, one soon becomes lost in an extraordinarily complex, living world–a microcosm in which a beautiful but deadly ballet is conducted on a microscopic scale (Rudloe, 1971). Hungry polyps, some resembling snapdragons, others looking more like daisies or tulips, expand their knobby, translucent tentacles, slowly flexing and languidly waving them about, lulling the observer with their slow-motion ballet — until they abruptly and quite unexpectedly snap up a bit of planktonic life, stinging it, drawing it in with one violent contraction, digesting it, and then re-expanding like a blossoming flower to hunt again (Rudloe, 1971). There are many such polyps in a colony, hundreds of them, each of which is armed with many tentacles and countless nematocysts, and at any given moment, some of them will be dormant and still, some will be expanded and lazily casting about for prey (Rudloe, 1971), and still others actively feeding (Abbott, 2003)."

The feeding or nutritive zooids are the distinct individual animals in a hydroid colony that are responsible for capturing and digesting prey; as such, they bear the nematocyst-studded tentacles. But you need high magnification in order to appreciate the true beauty of living hydrozoans, or to differentiate between different species of hydroids, or to observe the zooids going about their deadly business.

Hydroids are insidious because they start out so small and insignificant, yet spread so quickly under ideal conditions (e.g., a nursery tank or dwarf seahorse tank receiving daily feedings of Artemia nauplii). Many species can spread asexually by fragmentation as a microscopic speck of the parent colony. All of the troublesome types have a mobile hydromedusae stage, which look like miniscule micro-jellyfish, and can spread sexually in this way as well (Rudloe, 1971). The mobile medusae swim about with a herky-jerky, pulsating motion and are often mistaken for tiny bubbles due to their silvery, transparent, hemispherical bodies (Rudloe, 1977). These tiny jellies often go unrecognized until they begin to settle and are discovered adhering to the tank walls. They will have a large "dot" in the middle of their bodies and smaller ones at the base of their nematocysts (Abbott, 2003). (These are the nasty little guys you have a near six-gallon nano tank, mermaid, and they are serious threat to your seahorses.) Both the polyp stage and the medusa stage sting (Rudloe, 1977) and are capable of killing or injuring seahorse fry. Multiple stings can kill the babies outright, but they are often only injured by the nematocysts, which damage their integument and leave them vulnerable to secondary infections. Many times it is a secondary bacterial or fungal infection that sets in at the site of the injury which kills the fry.

Once they find their way into a dwarf seahorse setup or nursery tank, hydroids can explode to plague proportions very quickly because conditions are ideal for their growth: perfect temperatures, an abundance of planktonic prey that is renewed every few hours, and a complete absence of predators.

When hydroids become a problem in the aquarium, there are a couple of good ways to eradicate them and get the situation under control again, mermaid:

Eliminating Hydroids — the Heat Treatment and medicating the tank with Panacur

Heat Treatment

Some types of hydroids can be eradicated from the aquarium by raising the water temperature to 92°F or above for period of 3-5 days (Liisa Coit, pers. com.). Keep all of the filters and equipment operating so that the hot water circulates throughout them and destroys any hydroids or hydromedusae that may be present in the filtration system. (Seahorses and their tankmates, including snails and the cleanup crew, must be removed to a temporary holding tank while the heat treatment is carried out.) Maintaining the water temperature at 92° for this period does not harm the beneficial nitrifying bacteria in your biofilter, injure marine plants or macroalgae, or kill off copepods and other beneficial microfauna (Liisa Coit, pers.com.).

After the treatment period, perform a large water change to assure that the die off of hydroids does not degrade your water quality, and adjust the water temperature back to normal, and all the animals can be returned to the aquarium. The tank will not undergo a "mini cycle" and there will be no ammonia or nitrite spikes (Liisa Coit, pers. com.).

However, not all types of hydroids respond to the heat treatment method of eradication. The snowflake type of hydroids that are all too common seem to have no difficulty surviving the heat treatment. So generally speaking, then Panacur is a more reliable way to eliminate them. If your particular hydroids do not resemble snowflakes, mermaid, then there is a chance that the heat treatment will be effective.

The other alternative is to treat the tank with fenbendazole (Panacur) while the seahorses and macroalgae are present, as explained below:

Eradicating Hydroids Using Fenbendazole (brand name Panacur)

Hydroids can also be controlled in the aquarium by using a medication known as fenbendazole to treat the tank over a period of days. Fenbendazole (brand name Panacur) is an inexpensive anthelmintic agent (dewormer) used for large animals such as horses, and the de-worming granules can be obtained without a prescription from stores that carry agricultural products (e.g., farm and ranch equipment, farming supplies and products, veterinary supplies, livestock and horse supplies, livestock and horse feed). If you live in a rural area, those would be good places to obtain it as well.

However, there are a couple of things you should keep in mind when treating an aquarium with fenbendazole, mermaid. Administering a regimen of fenbendazole (FBZ) or Panacur will eradicate any hydroids, Aiptasia rock anemones, or bristleworms from live rock or live sand, thereby rendering them completely seahorse safe. The recommended dose is 1/8 teaspoon of the horse dewormer granules (22.2% fenbendazole) per 10 gallons of water, if no baby seahorses are present in the aquarium. Dose aquarium with 1/8 teaspoon/10 gallons every other day until you have administered a total of 3 such treatments (Liisa Coit, pers. com.). Even one dose will do a fine job of eradicating bristeworms, but Aiptasia rock anemones and hydroids are a bit tougher and may require 2-3 doses to eliminate entirely.

If baby seahorses are present, reduce the dosage to 1/16 teaspoons of 22.2% fenbendazole granules per 10 gallons of water, and administer three doses every other day, just as described above.

Because fenbendazole is essentially a de-worming agent, it will destroy any bristleworms, flat worms, spaghetti worms or the like, in addition to hydrozoans.

Fenbendazole does not have any adverse effects on biological filtration, but be aware that it is death to many Cnidarians besides hydroids. Mushrooms and related corals are generally not affected, but expect it to have dire effects on other corals (e.g., sinularias), polyps, gorgonians, and anemones. In general, any Cnidarians with polyps that resemble the stalked family of Hydrozoans are likely to be hit hard by fenbendazole, so don’t use this treatment in a reef tank! (You will need to remove your gorgonia and any other live corals during the treatment period, mermaid, and then be very careful when you return them to the aquarium to make sure you are not giving any remaining hydroids the gorgonia could be carrying a free ticket back into your seahorse tank.)

Also be aware that fenbendazole seems to soak into the porous live rock and be absorbed indefinitely. I know one hobbyist who transferred a small piece of live rock that had been treated with fenbendazole (Panacur) months earlier into a reef tank, where it killed the resident starfish and Astrea snails. So enough of the medication may be retained within treated live rock to impact sensitive animals months after the fenbendazole was administered. Don’t treat live rock intended for reef systems with fenbendazole (Panacur)!

At the lower dosage recommended for nursery tanks and dwarf seahorse tanks with fry (1/16 tsp. per 10 gallons), fenbendazole normally does not harm cleaner shrimp and decorative shrimp. But it is deadly to most type of snails. For example, Trochus or turbo snails, Astrea snails, and especially Margarita snails are sensitive to the medication and must be removed from the aquarium until the treatment regimen has been completed and the fenbendazole has been pulled from the aquarium using activated carbon and/or polyfilter pads for chemical filtration. On the other hand, Nerites, Ceriths, and Nassarius snails are less sensitive to the medication and can remain in the aquarium during and after treatment with fenbendazole. If you’re not certain what type of snails you have, it’s best to remove them until after the hydroids have been eliminated and any remaining traces of the fenbendazole/Panacur have been removed from the aquatic.

Fenbendazole (brand name Panacur) will kill starfish but crustaceans such as copepods, hermit crabs, and shrimp are normally not affected at all.

Macroalgae such as the feathery or long-bladed varieties of Caulerpa or Hawaiian Ogo (Gracilaria) are not harmed by exposure to fenbendazole at even triple the normal dose. In fact, if you will be using Caulerpa in your nursery tanks to provide hitching posts for the fry and serve as a form of natural filtration, it’s a very wise precaution indeed to treat them with a regimen of fenbendazole beforehand.

So fenbendazole (FBZ) or Panacur is primarily useful for ridding bare-bottomed nursery tanks and dwarf seahorses setups of hyrdroids and Aiptasia anemones, ridding Caulerpa and other macroalge of hydroids or Aiptasia before its goes into the aquarium, and cleansing live rock of bristleworms, hydroids, and Aiptasia rock anemones before it is introduced to the aquarium.

It can also be used to eradicate bristleworms, hydroids, an Aiptasia from an established aquarium if it does not house sensitive animals such as live corals and gorgonians, starfish, Astrea snails, or tubeworms and other desirable worms that may be harmed by FBZ, providing you monitor the ammonia levels closely and are prepared to deal with the ammonia spike that may result from the sudden of the worm population.

In short, fenbendazole is an excellent way to eliminate hydroids from dwarf seahorse tanks, as well as nursery tanks and rearing tanks or anytime they take over an aquarium and cause problems. If there are hydroids present, needless to say the newborns and small seahorses will find them very irritating, and may be killed outright as a result of multiple stings, depending on what type of hydrozoans you are dealing with.

Okay, mermaid, that’s the quick rundown on hydroids (both the colonial polyps and the mobile Medusa stage or micro jellyfish that you have) and the recommended procedures for eliminating them from your aquarium. In your case, I would set up a hospital tank with freshly mixed saltwater, give your seahorses a quick freshwater dip for external parasites, and then transfer them to the hospital tank for treatment with Nitrofuracin Green while you are eradicating the hydrozoans from your nano tank.

Best of luck eliminating the hydroids and getting your aquarium up and running again in good order, mermaid!

Respectfully,
Pete Giwojna

Dear mermaid:

Congratulations on successfully dipping your seahorses for the first time. Now that you know how to proceed, any subsequent dips should go smoothly and be much less intimidating for you.

When seahorses are suffering from external parasites, dipping them as we discussed previously is an excellent first aid procedure to start with. The seahorses may be temporarily stressed out from being handled and dipped in the freshwater, formalin, H2O2, or methylyne blue, but they should quickly recover once they are returned to the hospital tank or the main tank. Once they have had a chance to recover from the dips, the seahorses normally feel much better because many of the parasites will have been killed or dropped off of them while they are in the dipping container. They should therefore feel more like their old selves again, becoming more active and swimming and eating normally again. But the beneficial effects may only be transitory if the seahorses are returned to an aquarium with a heavy infestation of parasites and pests. Allow me to elaborate.

The type of dips we have been discussing will provide some short-term, immediate relief from external parasites for each easy horses, but the ponies are likely to become reinfested once they are returned to the main tank. The fact that your seahorses have resumed scratching themselves with their tails suggests that that is the case with your tank, mermaid, and they may also be reacting to the irritation from hydroid stings due to the hydromedusae microjellies. That’s why I suggested giving them a freshwater death and then transferring them into a hospital tank filled with freshly mixed saltwater so you could treat them with the Nitrofuracin Green.

That’s still what I would recommend. Set up a makeshift hospital tank with newly mixed saltwater as described below, give the seahorses another quick dip to cleanse them of some of the external parasites (dipping them in either freshwater, 3% hydrogen peroxide, methylyne blue, or formalin — whatever works best for you and you are most comfortable with — would do nicely for this step), and then transfer them to the hospital tank and treat them with the complete regimen of the Nitrofuracin Green, which works very well for treating mild skin infections. I am thinking that’s your best option for treating the seahorse with the "flakies" and your other seahorses should also benefit from the medication.

Setting up the Basic Hospital Tank

A bare-bottomed aquarium with plenty of hitching posts will suffice for a hospital ward or Quarantine Tank (QT). Ideally, the hospital tank should have one or more foam filters for biofiltration along with a small external filter, which can easily be removed from the tank during treatment but which can hold activated carbon or polyfilter pads when it’s time to pull the meds out. It’s important for the hospital ward to include enough hitching posts so that the seahorse won’t feel vulnerable or exposed during treatment. Aquarium safe, inert plastic plants or homemade hitching posts fashioned from polypropylene rope or twine that has been unraveled and anchored at one end are excellent for a hospital tank. No aquarium reflector is necessary. Ambient room light will suffice. (Bright lights can breakdown and inactivate certain medications and seahorses are more comfortable and feel more secure under relatively dim lighting.)

So just a bare tank with hitching posts is all you need for your hospital ward. No heater. No reflector. No lights. No substrate. You can even do without the sponge filters or external filter in your case, mermaid, just adding a couple of airstones to provide surface agitation and oxygenation. That’s it.

In a pinch, a clean 5-gallon plastic bucket (new and unused, NOT an old scrub bucket!) can serve as a makeshift hospital tank. It should be aerated and equipped with hitching posts and perhaps a heater, but nothing else. This makes a useful substitute when the Quarantine Tank is occupied or in use and a seahorse needs treatment.

Stay on top of water quality in the hospital tank/bucket with water changes as often as needed during treatment, and and when you are treating the occupants for a health problem, re-dose with the medication(s) according to directions after each water change

Let me know if your seahorses continue to scratch themselves when they have been transferred to the freshly mixed saltwater in your hospital tank and are undergoing treatment with the Nitrofuracin Green, mermaid, and I will explain how to administer hyposalinity to their treatment tank to eliminate the parasites that are apparently bothering.

Best of luck treating your itchy seahorses and reading your six-gallon nano tank of the mobile medusae micro jellyfish, mermaid.

Respectfully,
Pete Giwojna