Aggressive goldfish attacked 3 cardinal tetras?

Question

My son won a common goldfish (1.5 inch) during a school outing to the state fair. We got a 2.5 gal tank for it with pump/filter. We've had it for three weeks and it paced the tank and seemed either agitated, lonely or bored. Three days ago we added 3 small cardinal tetras (.5 inch each). I turned the light off last night, all seemed well. This morning, all three tetras were dead. All three were badly mauled. I think I have a killer goldfish. I wanted to give it company, but now I'm afraid he'll attack/kill anything I add. Would a betta be a safe addition? If not, what would be a suitable tankmate for him?

Answer 1

Cardinal tetras are tropical fish and should not be put into a tank with no heating system. The gold fish did not kill them but the cold water certainly did. If they were mauled it was probably done after death by the goldfish that thought the dead fish were just food.
If you want to give the gold fish company choose another cold water fish, any good aquatic store will advise you what is best.
I own a pet store and care sheets are free on my website
http://www.artsaquaticsandanimals.co.uk

Answer 2

Goldfish and tropicals really don't mix well. Actually your bigger problem is the size of the tank. 2.5 gallon is way to small for 1 goldfish... In a tank that size you're limited to a (1) betta or a couple white clouds. A goldfish really needs a 20 gallon plus. The put out so much waste and get fairly large so that you'll need the extra water.

Answer 3

The best tankmates for goldfish are other goldfish. Most tropicals, including bettas and neons have significantly different water requirements than a goldfish adding another would be the best choice.

I do feel that I should warn you that your one current fish will far exceed your tank as it is. Common goldfish frequently grow to 10" or more and 18" is not unusual. Be prepared to possibly swap the fish for a smaller one at al local fish store on a fairly regular basis. Most stores should be willing to make the swap for you if you explain the situation.

MM

Answer 4

You should learn a little more about things like tank cycling(yours isn't) fish compatibilty(goldfish and any kind of tetra require vastly different water conditions).Your goldfish is likely to die also just more slowly.Please do some research before killing more fish. By the way the guys at the big box pet stores aren't to be trusted. They sell fish,not advice. Find some good web sites or buy a book.

Answer 5

First the tank is much too small for your fish; you need 10 gallons for every gold fish. They are carp, and will grow to the size of the tank, I have some that lasted over 15 years and more, but they became very large fish. Secondly you said nothing about the water conditions for your fish. The prefer a PH of 6.0-8.0, and need frequent changes of water. A lack of a stomach means they put more waste in the water. They need large surface area, in addition to filtration. It is not necessary to heat a goldfish tank, and in some cases that causes a lack of oxygen in the water, which also leads death. You mentioned adding tetras to the tank, which like a PH of 5.0 to 7.0 so they are not really compatible with your goldfish. If you must have a companion, first get a bigger tank, at least 30 gallons to allow some fish growth, and then pair your fish with another gold fish. Remember that they will be producing twice the waste so be careful about the nitrates in the water and ammonia, use frequent water changes (and be sure to allow that new water to season before adding it, never use straight tap water which contains all kinds if harmful chemicals). Try to keep the nitrates between 20-50 ppm. If your fish is gasping at the top of the bowl it is in need of air, and this action, as well as eating food from the surface can lead to air in its digestive tract, which can eventually kill the fish. Goldfish, contrary to popular belief are intelligent and can come to recognize their owners and feeders, as well as other animals. Your goldfish is not a killer as such; it is doing what it would naturally do in an uncomfortable environment. Feed it pellet food made for goldfish, not flakes, keep the tank clean and the water changed, provide the proper size home for it, and any friends it may eventually have, and your fish will provide you with years of companionship. You will come to know its personality, and they do have varied ones, and it will learn to communicate with you. Our latest goldfish, Sushi Boy, who passed this year, was with us almost 16 years. He lived in a 150 gallon tank. One more thing, never touch your fish, that will remove the natural slime that is a protectant for its skin. Good luck with your fish, give it the best home you can and it will be a happy member of your family.

Answer 6

Just get a couple more common goldfish. They do come in a variety of colors. Try to get them near the same size as the one you have. This is really odd as goldfish are usually calm and easygoing little fishes. You are feeding the fish a regular goldfish food, right? Feed only as much as they can eat in 5 minutes. When you add fish, float in the bag they come in for 15 mins. to allow the water temp. to adjust to the tank temp. This also allows the resident fish to eyeball the newcomers. Good Luck.

Answer 7

My suggestion would be to try some other common goldfish. Don't get the fancy ones 'cause it'll just rip their fancy fins apart. No, a betta would NOT be safe unless you want to teach the goldfish a lesson. You could also get some of those tiny frogs. They are really cute and live strictly underwater and are good companions for goldfish (atleast, in my experience) and would probably interest your son more than the boring fish.

Answer 8

I would just suggest to get another goldfish if you want to give it company. But the very best thing to do is to ask you local fish store employees what fish you should put with it. Not all fish are compatible and many need different things such as fresh water, salt water, tropical etc. So when I buy fish I always ask the opinion of the person who I am buying them from. But it is true that sometimes even goldfish can be killer fish.

Answer 9

Your goldfish is just being a goldfish. They are members of the carp family, and are not good tank mates for most tropical fish. You should only really pair goldfish with other goldfish. Bettas are only aggressive with other bettas, by the way. They are fine when kept with other tropical fish.

Answer 10

Get some other common goldfish... feeder fish (what they are commonly refered to as) at the local pet store are about a dime to a dollar, pending on size. Two dollars usually gets you about a dozen little ones.

Common goldfish are social animals, and like to live in groups. They enjoy interacting with others of the same species and the overall breed is friendly. With proper care they can become quite tame, eating from hands and swimming frantically towards the owner.