Re:live rock

Pete Giwojna

Dear Karen:

Welcome to the forum!

Yes, unwelcome hitchhikers that find their way into the aquarium admits live rock are really concerned for seahorse keepers and its customary to minimize this risk by subjecting the live rock to various "debugging" procedures before it’s introduced to the seahorse tank, as discussed below:

Debugging Live Rock

Their a few ways you can cleanse your live rock to eradicate unwanted hitchhikers without harming the desirable organisms and beneficial bacteria it houses. For example, a hypersaline dip should work, or you could treat it with Panacur (fenbendazole in your hospital tank, and the old Club Soda trick may be the quickest, easiest way to go about it. I’d be happy to run through those live rock "debugging" procedures for you.

The hypersaline dips are pretty self explanatory. Just get yourself a nice big plastic bucket or Rubbermaid tub or styrofoam cooler/shipping box, fill it halfway with extra salty water, submerge the piece of live rock (LR) you want to cleanse of unwanted hitchhikers and give it a good soak. Pests like stomotopods (mantis shrimp), pistol shrimp, predacious crabs and bristleworms won’t like the suddenly change from normal-strength saltwater to the hypersaline bucket water and will bale out of their hidey holes in the live rock in a hurry in search of conditions more to their liking.

There are no hard and fast rules about how salty the dipping water should be or how long the dips should last, but it’s a good idea to use tap water for the dips (don’t detoxify it or adjust the pH — the bigger the shock, the quicker the pests will abandon the live rock, so a little chlorine in the water is a good thing). In general, adjusting the salinity in the dipping container to a specific gravity of around 1.042 (55-ppt salinity) is a good place to start. The saltier the water, the quicker the critters will bug out and the more thorough this debugging procedure will be.

Place something in the bottom of the bucket to keep the live rock elevated above the bottom (pvc pipe, a couple of bricks, plastic eggcrate from a light fixture — anything along those lines will suffice) and plunk the live rock directly into the hypersaline water. The mobile pests it harbors will soon crawl, slither or drop off the live rock, and, when you remove the LR after 10 minutes or so, the unwanted hitchhikers will be left behind in the dipping container.

The Club Soda trick is a similar technique that relies on carbonated water to flush out mobile pests rather than hypersalinity. Simply remove the live rock to an empty bucket and flush out the hidey holes thoroughly with a generous amount of straight, undiluted Club Soda. The carbonation in the Club Soda means the hitchhikers will be immersed in CO2, deprived of oxygen, and subjected to a drastic pH shift all at once. They’ll bail out of the rock in a big hurry! You can then rinse the live rock in a bucket of saltwater you have prepared in advance, to remove any lingering traces of the Club Soda, and return it to the aquarium immediately. Problem solved.

This method works well for surgical strikes in which you are flushing out a particular pest whose hidey hole you have already located. If you want to cleanse your live rock of unwanted hitchhikers in general, place the live rock in a bucket with just enough saltwater to cover the rock and then add a full 2-liter bottle of Club Soda (Liisa Coit, personal communication). Pour the Club Soda slowly over the surface of the rock, concentrating in particular on any cavities or crevices. This will drive out any mobile pests hiding in the rock, including crabs, mantis shrimp, pistol shrimp, and bristleworms, in a matter of moments.

Afterwards the live rock is rinsed in saltwater to remove the residual Club Soda, and is ready to be returned to the aquarium. (Any desirable critters that may have been driven out of the live rock — Gammarus, pods or snails, for example — can be netted out of the delousing bucket and returned to the aquarium as well, none the worse for wear.) Too much Club Soda can be deadly to microfauna such as gammarids and copepods, so if you want to recovery and revive the ‘pods, use more saltwater in the bucket and less Club Soda until you achieve the desired results.

Fenbendazole (brand name of 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) or via the Internet from places such as KV Vet Supply (see link below). The granular form of fenbendazole (horse dewormer granules 22.2%) is preferable to the paste for aquarium use, as the dosage of the granules is easier to regulate (Liisa Coit, pers. com.). It is available in packets of 5.2 grams or 0.18 ounces.

Click here: KV Vet Supply / KV HealthLinks – Pet, equine & livestock supplies / Quality nutrition for you!

(Use the 22.2 % granules rather than the paste.)

Administering a regimen of fenbendazole (FBZ) or Panacur after a hypersaline bath has chased out the mobile pests will eradicate any hydroids, Aiptasia rock anemones, or remaining worms, thereby rendering your live rock completely seahorse safe. The recommended dose is 1/8 teaspoon of the horse dewormer granules (22.2% fenbendazole) per 10 gallons of water. Dose the live rock 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.

Because fenbendazole is essentially a de-worming agent, it will destroy any bristleworms, flat worms, spaghetti worms or the like. The FBZ or Panacur treatments are best administered to the live rock in a bucket or hospital tank before the LR is introduced in the main tank. Otherwise, the massive die-off of the worm population in the aquarium may require large water changes in order to prevent a dangerous ammonia spike! And after the treatment is completed, its a good idea to add a portion of newly purchased live sand to the system in order to help restore its normal diversity of fauna and microfauna again (Liisa Coit, pers. com.).

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!

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. With the exception of Astrids (Astrea), Coit and Worden have found it does not usually affect the types of snails typically used as cleanup crews (e.g., Nassarius, Ceriths, and Nerites). It will kill starfish but copepods, hermit crabs, and shrimp are normally not affected.

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 death of the worm population.

But the greater seahorses are not bothered by hydroids, which can be so troublesome for miniature seahorse species, Aiptasia rock anemones in the aquarium can easily be controlled by Peppermint Shrimp (Lysmata wurdemanni), and bristleworms are largely harmless except in plague proportions, so if you’ll be keeping Mustangs, Sunbursts or any of the large breeds of seahorses, treating your aquarium or pretreating your live rock with FBZ may not be warranted. In such cases, giving the live rock a hypersaline bath before it goes in the main tank is generally sufficient to drive out mantis shrimp, predatory crabs, and the like, and will usually flush out enough of the bristleworms to keep their numbers in check.

Best of luck eliminating unwanted hitchhikers from your seahorse tank, Karen!

Happy Trails!
Pete Giwojna

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