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Swim bladder

PostPosted: Thu Jan 11, 2018 12:15 pm
by Photoman
Hi. I bought 5 Bleeding Heart/Koi angles. all were fine for 6 months. 3 developed swim bladder and died. I check my water and all is well. I am wondering if the inner breeding could cause this disease? All fish came from the same breeder.

Re: Swim bladder

PostPosted: Thu Jan 11, 2018 4:10 pm
by Diana
Close inbreeding can be part of the problem. Fish (and other animals) can be bred to close relatives as long as the breeder is diligent about culling. Without really good culling any genetic problem can be passed on and reinforced. A fish of a particular species that is selectively bred to show a particular color, and to breed true to that color will indeed be inbred to reinforce that color. The side effect of this close inbreeding does indeed suggest that it could be weak in other ways. A good breeder will keep records, cull, and not re-breed parents that produced too many defective fry.

A fish that is doing fine in one environment could be said to be genetically suited to that setting. When the fish is moved then something different (or even the move itself) can stress the fish beyond what it can handle. This stress can weaken the immune system, so some kind of bacteria or virus can attack. Fish that are not closely inbred may have a genetic variation that allows them to adapt to the new setting, and a stronger immune system to stand up to the stress of the move.

Swim bladder issues can be from any of several initial problems.
If the swim bladder is mis-formed, but the fish are maintained in conditions that do not aggravate this problem, the fish may survive, even breed. But the slightly mis-formed swim bladder is likely to be passed on, and perhaps made worse in the fry. This in itself may be enough stress, or else the move when the fish are sold is too much stress. Then an infection can move in.
The swim bladder is tied in to the rest of the fish, so that a problem with some other system can affect the swim bladder.
I am not sure this happens in Angels, but in fancy goldfish the distorted bodies can affect the digestive tract and swim bladder so the fish can flip upside-down or get constipated.

Unfortunately a swim bladder problem cannot usually be cured. First of all, there is the possibility of a genetic problem, but also there is the problem of not knowing what to treat. A virus cannot be treated, but antibiotics might work against bacteria. The problem here is that once the fish is showing signs of a swim bladder problem it is probably too late to cure the fish. You might help the fish to kill off the bacteria, but the damage to the swim bladder has usually gone on too long to be corrected.