I guess that would depend on your definition of smart. :) Studies have shown that goldfish and can retain information for up to 3 months (not 30 seconds). Other studies have detailed how goldfish are able to use visual landmarks and cues to navigate mazes, and even remember how to get through those mazes two weeks later. Researchers even reversed, removed and altered the visual cues, with little impact to the fish's performance. There's ample evidence that goldfish are capable of learning tasks and finding multiple ways to achieve one goal. The studies are interesting. :)
Since this is a simple question, no. Hell no.
You obviously can but it is not the correct food so it will not do the right job. Manufacturers have spent millions of dollars designing and producing special foods for different species of fish to keep them as healthy as possible. The smart thing would be to feed goldfish food to goldfish and cichlid food to cichlids.
Any fish large enough to swallow a goldfish will probably do so. Most fish eating birds will also eat them. Then of course there are the human idiots. People who swallow live goldfish because they think it is a 'smart' or 'in' thing to do.A goldfish does not have a predator, but it can still die from lack of food or water.
Some common breeds of goldfish are: the Black Moor goldfish, the Ryunkin goldfish, the comet goldfish, the common goldfish, the Calico Fantail goldfish, the telescope eye goldfish, the bubble eye goldfish, the pearl scale goldfish and the Oranda goldfish.
Commercial Goldfish food is cheap. Specialists have studied and millions of dollars have been spent designing and producing fish foods that are safe to use and suitable for feeding to fish. Why try to give your fish a hard time? Yes your goldfish will eat some human foods but most of it will foul the water and poison the fish. Be smart and use proper goldfish food. Your fish will appreciate it.
No you cannot put a frog with goldfish; goldfish belong with goldfish
Goldfish have a layer of slime on their bodies, it is their protection against disease and parasites and so it should not be damaged. Handling or stroking them is not smart simply because of that reason. Obviously they should never be stressed out by removing them from the water unless there is a jolly good reason to do so.
Most believe 2 or 3 seconds but it is proven that it is 3 months or so Look Up comet the gold fish Proves it is smart
The plural of goldfish is goldfish. It is the same as the singular.
Goldfish do not have legs. Goldfish do have fins, although the number of fins will depend on the type of goldfish.
Goldfish do not deliberately kill themselves. They have been known to jump out of tanks if the owner wasn't smart enough to put a well fitting cover glass on their tank. Bad water conditions can make fish dash and jump in an attempt to escape their container too.
there are three basic breeds: fantail goldfish, comet goldfish, and common goldfish. if you are getting goldfish for the first time, i would recommend common goldfish as they need the least care.