weak snick – cause / theories

There seem to be a lot of theories out there about what causes "weak snick"/"trigger lock". Unfortunately for me and my fish, I have had LOTS and LOTS of seahorses affected with the condition. All but one have died from it.

The bright side is that I have had the opportunity to study the "weak-snick" seahorses very closely, and experimented with several different treatments. I have also read and analyzed every single case I could find reported on the Web, and as a result I believe I have found the exact cause of this mysterious ailment.

I believe I should share my observations and my theories with you. Opinions are welcome. I am not a biologist nor a researcher, but I am a physician, and I know quite a bit about pathology, about infections, and medical treatments. I am confident about my findings. Hopefully, by sharing my theory, we can avoid any more premature, needless seahorse deaths.

First of all, "weak-snick" is NOT caused by parasites, and cannot be cured with anti-parasite medications (using them makes matters worse!). It is NOT caused by any bacteria either. (-Paradoxically, using antibiotics may seem effective -more on this later…) Weak-snick is NOT caused by any nutritional or mineral defficiency. And it is deffinitely NOT caused by a piece of gravel stuck in the snout !!! Although it can result in muscle or ligament injury, the physical lession is NOT a random event, nor is the injury the initiating event -but rather the LAST stage in the condition. There is also nothing actually "locked" in "trigger-lock".

Weak-snick is a complex NEUROMUSCULAR disorder. In seahorses, it affects nerve conduction velocity, resulting in neuromuscular "incoordination"; this impairs the fish in both starting and completing the normal "snick" action. The condition manifests itself with several sublte early signs and symptoms, and is only in the end, after several days or weeks that the damaged nerves and muscles in the mouth finally tear and rupture, and the fish can no longer feed.

"Weak-snick" presents itself under circumstances that MIMIC parasitic infestation, but in reality there are NO parasites involved. "Trigger-lock" is the end-result of a NEUROPATHY caused by DRUG POISONING ! A "weak-snick" seahorse is a POISONED seahorse. The best treatment, of course, is prevention, but once "jaw-lock" occurs, the best remedy is DETOXIFICATION.

Ironically the "weak-snick" seahorses have been poisoned the very same "medications" we use to keep them from getting ill in the first place.

Here is the typical profile of the "trigger-locked" seahorse:

Its owner -like me- is a fairly novice aquarist. We have a history of having lost several seahorses in the past -despite our best care and intentions. We consider ourselves "unlucky" with seahorses, and we blame "parasites" for their deaths.

The fish will likely have been kept in a small, fish-only tank, with few invertebratees, and no corals. The water tamperatureis will likely be high for a seahorse tank (78 degrees or higher). There will probably have been a new fish introduced to the tank recently, or a fish may have fallen ill or died recently in the tank. Fearing a parasite infestation, the owner will treat the fish, the quarantine tank -and even the display tank- with "preventive" anti-parasite medications. "Experts" warn us to never add medications to the display tank -but we do it anyway ( -because we bought some medication that is described as being "safe on most fish", and "filter-safe".) Plus, we have NO CORALS in the tank to worry about..!

At first, all the fish will look healthy; then suddenly, one seahorse stops eating, another develops difficulty breathing, and another develops "trigger-lock". Fearing yet another parasite plague, the aquarist gives several more doses of medication to the fish -AND the display tank- in an effort to eradicate the mysterious, invisible parasites.

Strangely enough, the weak-snick seahorse itself shows no difficulty breathing, no unusual spots, no cloudy fins, no "snout-rot" at all. In a way, it looks healthier than all the other fish. After a few days or weeks, EVERY SINGLE seahorse will be sick, and several will develop "trigger-lock" in rapid sequence -or at the same time. It all resembles a parasite infestation. The owner, in desperation, gives several more doses of "medication". Within days, many of the fish are dead, and the "weak-snick" seahorse is still alive, but starving, alone in the hospital tank.

This is the typical, sad story of "weak-snick". The cause is not parasites, but DRUG INTOXICATION -from either acute or chronic exposure to dangerous, toxic fish "medications".

Experts warn us novices to never add medications to the display tank, but when we keep losing our precious fish to mysterious illnesses an invisible parasites, we are all too tempted to use medications to "sterilize" the tanks, and eradicate any posible pathogens that may be making our fish ill.

Chemicals like Formalin, Aciflavin, Malachite Green, Copper and Methylene Blue are described as "medications" in the aquarium hobby, but everyhere else they are considered POISONS. Believe me, I am a Physician, and I would never prescribe Formalin or Malachite to a patient. ( -nor would your Vet ever prescribe them to your dog!) These chemicals are actually BANNED in many countries, and are banned in the US on food products.

A chemical intended to kill one animal within minutes (yes, protozoans ARE animals) cannot be expected to be safe for another animal despite continued exposure for hours, days, even weeks.

With the exeption of copper, no other chemical used to kill parasites in a fish tank can be measured in the water. And there is no way to accurately predict the real degradation rate of any drug in the tank between doses. Even if we do partial water changes, a water change can only remove an equivalent fraction of the drug present in the system. Even the best activated carbon cannot remove 100% of any chemical in the water. As a result, the practice of adding "preventive" treatments to the tank water (and SEVERAL doses) every time we buy a new fish only garantees that the drug level in the tank will only keep getting higher and higher every time we use it. Eventually, these chemicals will do permanent organ damage to our fish.

All of these "medications" are well known to cause significant liver and kidney toxicity. But of all, the worst offender has to be Malachite Green. Reasearch has shown that in addition to kidney, liver and muscle damage, Malachite forms permanent deposits in ALL fish tissues. It slows down nerve conduction velocity, and causes "neuromuscular incoordination". It is the combination of metabolic and hepatic "encephalopathy" plus neuromuscular incoordination that in seahorses results in "weak-snick" and "trigger-lock".

The first signs of toxicity are subtle. When the seahorse is new, it is typically very active and alert. When offered food it "attacks" it immediately, taking no time to "snick" it. After the fish is exposed to water that has beed previously treated with anti-parasite drugs, the fish gradually becomes a bit more lethargic, more slow. It swims around less, and assumes a less vertical posture. The fish will also curl its tail less, and sometimes drags the tail on the bottom. When offered food, the fish might stare at a piece for several seconds ( -as if it could not decide to it or not !) The skin color may also get a little darker, and the stool may become more oily. All of these signs may resemble a parasite problem -causing the owner to misdiagnose and mistreat the condition. But the fish is actually intoxicated -not infected.

The first obvious sign of "weak-snick" is when the audible "click" disappears when "sneaking" food. The affected seahorse may also seem to extend more of its body when "snicking". Then, in a single feding session, the fish will seem to "miss the target", or need to take two attempts to get the food in. Then suddenly the seahorse’s snout will seem to get "stuck" -and the fish will fail to get any more food in. The fish will try again and again, but the feeding mechanism will seem to be "stuck" permanently. If not treated correctly, the fish will starve to death.

Here is what is really going on:

During normal "snick", a "wave" of motion is generated starting with extension of the neck, followed by an invountary "reflex" deployment of the hyoid "trigger", followed by expansion of the snout, and finally the opening of mouth. The mouth opens only after a very brief delay. But the snick motion is only half-done. The food gets into the snout because the motion CONTINUES: After the mouth opens, the neck continues to extend, the trigger continues to move back, and the snout continues to expand. This continued expansion of the oral cavity is what sucks more water (and food) in. But the mouth must open at a very EARLY and PRECISE moment.

The first half of the "snick" action generates a strong "negative pressure" inside the snout. The mouth muscles must be healthy and strong enough to overcome the high pressure gradient between the inside and outside of the mouth. The longer the nerve conduction is delayed, the higher the pressure gradient, and the more effort is needed to open the mouth. In time, drug toxicity will weaken and damage the muscles and ligaments of the mouth, making "snicking" harder -yet slower each time.

Eventually, the mouth muscles will strain and tear under the pressure. With the mouth muscles injured, the mouth simply cannot open any more, and the vacuum generated by the early part of the "snick" keeps the lips shut tight. The high external water pressure will opose any movement in the direction of any expansion of the snout -thus giving the snout the "locked" appearance. But this is only an ILLUSION ! There is NOTHING actually "locked".

Soon, the affected seahorse will start to do "yawns". During the "yawn", the neck will extend fully, the snout will expand, and the "hyoid -trigger" will move FREELY. This shows that all these components are indeed intact and free to move normaly. One exeption: The mouth may or may not open during the yawn. If the fish can open its mouth well, then it only has "delayed nerve conduction" and the prognosis for recovery is good. If the mouth opens very little or not at all during the "yawn" then there may be significant muscle or ligament injury, and the fish may never recover.

If you currently have a seahorse with "trigger-lock", this is what I would recommend:

Remove the fish to a clean, medication-free tank. The fish needs to be "detoxified". You may do a brief, 5-10 min freshwater and formalin dip to be sure that the fish has no gill parasites. You may consider adding some vitamins and mineral supplements to the water, but give no medications. Consider a large-volume water change on the display tank, and replace the activated carbon with a fresh bag.

Some people have used Melafix to cure weak-snick. It might have worked -but only as a placebo. As long as you do not expose the fish to other more toxic anti-parasite drugs, the fish should improve ( -with or without Melafix…) I personally consider Melafix unnecessary and very dangerous. I don’t recommend it. The best experience in recovering from weak-snick is from those who have given the fish no special treatment at all ! The worst results are from those who kept treating for parasites.

I would recommend that the fish not be fed for the first 5-6 days. It sounds cruel, but the fish can’t eat anyway, and any attempt to "snick" will do further damage to the injured muscles. Like any other musculo-skeletal injury, the tissues need rest, and time to heal.

After 5-6 days, place the fish in a breeder net, add a holdfast, and offer the fish some enriched brine shrimp. Brine shrimp is softer and lighter than Mysis and should be easier for the seahorse to eat. With luck, the seahorse will learn to "slurp" the brine shrimp without "snicking" (using its snout like a drinking straw.) Tube-feeding should be considered only if the fish does not learn to "slurp", and is not eating at all.

It may take at least 2-3 weeks (and possibly more) for the fish to recover. With luck and some TLC, the seahorse should eventually start to "snick" again. Once "snicking", you may start to offer some Mysis.

Again, prevention is always the best tretment. After all, it is just as simple as following the "experts" advise: NEVER add "medications" to the dispplay tank. and if possible, NEVER expose your fish to prolonged "preventive" medication treatments.

To avoid toxic chemicals from accumulating in your hospital tank water over time, do large-volume water changes BEFORE and AFTER each treatment.

Always treat a sick fish in a hospital tank, and avoid the temptation to medicate the display tank "just in case".

Well, that is my theory. I can’t prove it, but I feel confident in my observations, and in my advise. If anyone disagrees, opinions and feedback are welcome.

Good luck.

Jliano