What kind of fish should I get?

Bettas are good, just remember only one, they fight!

I had the *HARDEST* time starting up a school of Cardinals, and I am not an entirely unexperienced aquarist. All the other fish in my community tank did quite well...I have a mix of baby Angels, Platies, Kuhli Loaches, 2 Dwarf Gouramis and a Pleco in my 110 L tank, all with no problems after 2 months of setup. But over this period, I tried to introduce school after school of cardinals (maybe about 40 total in several batches) into the tank, and they all died rather suddenly, ranging from within hours or under a week. All this was mysterious as none showed signs of harrassment or specific sickness. They would just stop eating one day and be found dead the next, one at a time. I tested my water for nitrates, pH, everything you could think of and it was high in quality. I had all but given up, when one day I decided to make one last go of it, and bought 6 more fish from the same store and added them. This time, they did well from the very beginning, showing no signs of weakness and competing the first day for food. Today, they are among the most hardy of my fish. In the end, I attribute this success to two things: 1) the tank took longer to establish than I thought even at 2 months, some of balance had not entirely established in the tank and 2) the batch of Cardinals I bought this time were simply from a better source (although it was the same store, they had been subjected to less stress during their transport). Cardinals are extremely succeptable to small changes in water quality, and anyone who wants them as much as I did should not take this point lightly. Once they get started however, Cardinals are not only beautiful but even robust little fish.

Well personally tropical fish are easier than goldfish and if you get a marineland dualtemp heater you don't really have to worry about the tank getting over heated. I have experience with both goldfish and tropical fish. However there are some "tropical fish" that can tolerate room temp water like betta splendens or siamese fighting fish. I currently have two of them in seperate tanks as they will kill each other if placed togethor. I hope this helps.

Comets actually have lifespans of 30 plus yrs and grow to 12-14 inches. They also need 20 gallons PER fish when they are baby-juveniles. Adults need atleast 50 gallons per fish. Thats probably why it died, that and you werent cleaning the tank enought.

Goldfish are extremely messy fish and one fish in a 10 gallon tank needs atleast 40 percent water changes every week.

I dont get why people think heaters are a bother. An 8 inch 50 watt heater costs only about 7 bucks and all you do is set it in the tank, wait an hour, then plug it in and set it to the desired temp wich is 78 for most tropical fish and ta da your all set. Small community tropical fish such as platys, mollies, guppies, bettas, ect are more colorful, and not as messy then goldfish.

If you still insist on no heater then your options are drastically limited to

white cloud mountain minnows

http://badmanstropicalfish.com/profiles/profile46....

zebra danios

http://badmanstropicalfish.com/profiles/profile54....

bloodfin tetras

http://fishprofiles.com/files/profiles/593.htm

All of these fish need to be in groups of 3-5 but i wouldnt put more then 6 fish in that 10 gallon total. An understocked aquarium is easier to care for then an overstocked one. But definatly no goldfish because i dout you would upgrade to a bigger tank when 1 fancy goldfish outgrew that dinky 10 gallon wich is all you could put in it, is 1 baby-juvenile fancy goldfish (ryukin, moor, fantail, oranda, ect). Here is a picture of a 15 inch oranda named Bruce http://img.photobucket.com/albums/v704/ladycrotalu...

Info on cycling http://fins.actwin.com/mirror/begin.html

Here are caresheets on goldfish so you dont go bringing home another one from the fair wich is a cruel practice and should be boycotted.

http://www.goldfishparadise.com/care/care.php

http://www.peteducation.com/article.cfm?cls=16&cat...

http://www.mu.edu/~buxtoni/puregold/home.html

http://www.goldfishinfo.com/setup1.htm

http://www.fishpondinfo.com/gfish.htm

http://www.thegab.org/Articles/GoldfishBasics.html

You may as well just get another Goldfish....... perhaps a fancy one such as..... a Ryukin http://en.wikipedia.org/wiki/Ryukin

or a Fantail http://en.wikipedia.org/wiki/Fantail_(goldfish)

On the otherhand, A tropical tank is easier than you think once you've attached a heater + lamp....... easier still with a Bi-Orb tank set up http://www.biorb.com/

If you do change your mind about Tropicals, GUPPIES are pretty easy to take care of. The ones in my Dad's fish tank breed like rabbits, and don't think had to buy anymore fish since at least 10 - 15yrs ago. http://www.aquaria.info/modules.php?file=speciesde...

Also, Catfish can be quite unusual & interesting, such as the "Upside-Down Catfish" http://www.scotcat.com/factsheets/s_nigriventris.h...

or the just plain wierd & ugly Bristlenose Catfish http://en.wikipedia.org/wiki/Bristlenose_Catfish

Or then there's the NEON TETRA... a shoal of them in a tank can be good to watch http://en.wikipedia.org/wiki/Neon_tetra

What size aquarium does she have? It would be easier to make good suggestions if we know how large the tank is...for example, anything smaller than a 10-15 gallon aquarium would be too small to properly house a single goldfish.

Your little sister is probably a beginner aquarist so your best bet would to be go with a betta or a goldfish. Their are many types of goldfish that look cool and are easy to take care of. Bettas are easy to take care of but atack othe rfish especialy other bettas.

Betta

i would definately not put an oscar in a ten gal... you could put any cichlid that stays under 6 inches in there and be fine. if you got an oscar youd have to upgrade tank sizes soon, and thats expensive. electric yellow cichlids r a very bright fish and will stay small enough... dont get more than one cichlid for that tank, and dont put anything small enough to fit in its mouth in with it. cichlids r very hardy but produce alot of waste, so a small pleco or loach would help. i would suggest a species of pleco that doesnt get bigger than 6 inches(there are many) and that you get a pleco no matter what else you get(or loach)

Bettas are great fish to have. They don't need a heater or anything. Very low maintenance, and are beautiful to look at. I have two that are over two years old. Just don't put them together, they will fight each other, males.

An Oscar, they generally like to be fed by one person, they shouldn't be put with other fish though. They grow fairly large according to the tank size and you can have more then one together just make sure they are babies went you get them, because they do fight to kill.

Fighter fish are also very beauitful but should be kept on their own cause other fish will eat their beauitful long fins, and together with other fighter fish they also fight to kill. Unless you put two female to every male. Males are the pretty ones.