Backyard Aquaponics

HSM Disease, Disaster and recovery
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Author:  Sleepe [ Oct 11th, '13, 16:14 ]
Post subject:  Re: HSM Disease, Disaster and recovery

So basically Rupe and Tasty have a 50/50 on this? Inherent or in the water with a stress problem some; introduced (given specie difference to survival) ? Mind I can't see fish injecting themselves or have others helping them. :lol: :drunken:

Author:  TCLynx [ Oct 14th, '13, 21:28 ]
Post subject:  Re: HSM Disease, Disaster and recovery

LOL, When I see a statement like
Fungal diseases are treatable but bacterial are not!?!?!?!

Most "fungus" illnesses on fish are actually bacteria but people just call it a fungus because they can see it.

Anyway, as noted for backyard scale systems, rarely is any medication going to be worth while since it would require removing the fish to an isolation system and treating it there and the stress of putting the already sick fish in a separate system, probably without a good bio-filter, is rarely going to make for a good outcome.

Most of the time it is far better to keep the fish healthy with good water quality, reasonable stocking levels, and minimal stress. Of course I always recommend "quarantine" if at all possible so that you don't have to risk putting new fish directly into a big system, you want to keep them where you can observe and make sure you are not introducing a terrible illness or parasite into your larger systems and a smaller system will be far easier to treat for things like Ick or to sterilize and start over if something really terrible happens.

That said, the only real fish diseases I've ever experienced have been collumnaris and fin rot. The fin rot was in tilapia and I actually think it was domestic violence of having two female tilapia in with one male at a temperature too cool for the females to be up to laying eggs. It was only the females suffering from the problem.
The Collumnaris disease is very common when dealing with channel catfish. It is a bacteria that is commonly present in their environment and the best defense is to avoid stress and injury. Poor water quality can cause severe outbreaks that are common in the fish farming industry as the weather warms and the farmers are trying to up the feed and often go a bit too far. The disease seems to be less of a problem when water temperatures get above 80 F (at least that is what I've been told.) Net injury can also create a major opening for the disease to attack injured fish and hence my rule of minimal handling of my catfish since I noticed it would be far more common to have dead fish show up the week after we were netting fish out two days in a row the previous week. Now the rule is to only net fish once a week max and if you catch it, you take it, no dumping them back because you wanted a bigger one.
When I move my channel catfish from quarantine to their grow out tank, they get a salt/aloe bath on the way from one tank to the other to help keep their slime coat robust and avoid too many injury deaths after the move.

I get lots of people contacting me because they have catfish dieing in a new system. Many of them e-mail me saying they have Ick but they describe white patches not white bumps. White patches on the back or tail is more often Collumnaris. Channel catfish can't handle high levels of salt so I usually only recommend salting to 3 ppt MAX and doing everything possible to reduce stress and keep water quality at its best. If a fish is so sick that you can net it out without chasing it all over the tank and stressing/injuring the other fish, then pull that one out. If you have to go stressing and injuring all the other fish to catch one sick one, you will likely have many more sick ones on your hands in which case you might be better off pulling them all out and feeding them to the dogs and chickens.
I have had some fish recover from the white patches but once you can see the flesh, that fish probably won't survive.
Almost always people have stocked their system with 2-4 times too many fish, they have poor water quality, uneaten feed, and this is what causes the outbreak. Channel catfish have sensitive skin (no scales for protection) and ammonia spikes can quickly leave them with a weak slime coat and open to disease outbreak.

Once a batch of fish has had a bad outbreak, the survivors seem a bit more likely to experience a relapse. This has been my experience.

Collumnaris is contagious between fish but the stress and water quality play a large roll in the outcome. I would not go exchanging water between two systems if one system is experiencing an outbreak at the time since visibly sick or dead fish will be shedding high amounts of the bacteria but as noted, if a fish is not stressed or injured it may not get sick but since stress and injury is not always under our control, bio-security between systems should be a consideration.

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