FishDepot: There is no temperature concern! The myth about goldfish NEEDING cold water is just for human convenience. Goldfish grow slower in cold water. Their metabolism is slower so they don't produce as much waste. They are more convenient for humans to care for.
In warm water they outgrow their tanks faster (how horrible!). They digest better and therefore dirty a tank faster. They use more oxygen. In warm water they also reduce their chances for some diseases and their immune systems are better.
Most people who breed and show goldfish keep them in warmer water than do people who keep them as simply fish pets. Its a lot easier to produce a healthy, good quality specimen in warm water.
If you've got the resources to care for a large healthy goldfish, use warmer water.
The only concern I'd have is the slow-moving goldfish being nipped at by the other species. Not only so they go for fins, but they love the slime coat. Plecos can be especially deadly for a slow-moving goldfish.
This is only my opinion-for what it is worth!!!!!!!!!!!!!!!!!!!!!!
Any animal who is destined to be kept in captivity as a pet has the "RIGHT" to live in an environment that will not severely stunt its growth or shorten its natural lifespan.
That myth is NOT
just for human convenience. Goldfish can live in warm water Yes! BUT
they don't like it - they prefer a temperature that is around 68* which is not suitable for tropicals. Goldfish are not tropical fish otherwise they would be classed as such.
Some people also do prefer goldfish to tropicals because they love them not just because they are more convenient to maintain.
Kept in constant warm temp. will greatly shorten the lifespan of goldfish & is detrimental to their health. They need high oxygen levels which is greatly lessened in warm water.
Water Temp. is not the only thing to be considered - Compatibility is a big issue. A lot of tropical fish can be very nippy & go after slow swimming & long finned fish - the Goldfish is an easy target & will get picked on, adding even more stress.
Goldfish also have different nutritional needs - They need more protein & carbohydrates in their diet than tropicals do.
Goldfish also need more space.
AGAIN!! Any animal who is destined to be kept in captivity as a pet deserves & has the "RIGHT" to live in an environment that is as close to it's natural environment as possible & one that will not severely stunt its growth or shorten its natural lifespan.
EVERYONE PLEASE THINK ABOUT IT!!!!!!!