piranha health question

[champ1]

why do people say dont give your piranha feeder fish or gold fish froma pet shop because they could get your piranha sick? but in the wildthey eat sick, old or weak fish. what gives?

 

[champ1]

I meant wild they .not wildthey

 

[Lupin]

Because in captivity, feeders have been kept in very poor conditions. Want ich? Parasites? Anything bad affecting your piranhas is complete disaster afterwards.

 

[wataugachicken]

in the wild they may eat a sick fish once in a while, but they are going to eat whatever they can catch, including younger fish who haven't developed the skills to hide or escape properly, or fish with genetic deformities, or perfectly healthy fish who just weren't paying attention. plus, not only are feeder goldfish very prone to disease and fatty, they have an enzyme which breaks down thiamine, leading to a vitamin B deficiency in fish that eat a lot of them. this leads to an insufficent immune system, which means that your fish is much more likely to get sick.

the best options would be to grow your own feeders (livebearers or convicts), feed non-fish live food (earthworms, crickets), or feed frozen fish.

 

[guppy]

All of the above,
It is not bad to feed an occasional healthy goldfish to predators but there is a trick to that as feeders are often diseased. Not only are they raised in very crowded conditions but they are often overdosed on copper sulfate and methylene blue.
The other problem with goldfish and rosie reds is that they contain an enzyme named thiaminase that prevents the absorbtion of the vitamin thiamine, leading to a degeneration disease. As a treat this is not so bad but as a steady diet it can cause problems.
Best case is a well varied diet.