Best fish for a 10 gallon tank

Question
QUESTION: Hi!
I have a 10 gallon tank that I'm having trouble with.  My ideal tank would be full on fantail goldfish, but I'm reading that my tank's too small for that.  I had some goldfish in it but then I had an outbreak of ich and lost the whole tank.  Right now I have 2 very small comets in it barely an inch long.  I had 5 in there 3 days ago but 3 have died so they're not doing so hot.  I wonder if my filter or aerator is too strong...
How many goldfish do you suggest I start with.  I'd like to have at least 2 so they have some company.  What sizes?  Should I go for a tropical aquarium instead?  Are there any fish that wouldn't need a heater?  
I guess my main goal is to have a 10 gallon tank with a few healthy fish, whatever they are.
I appreciate your help!
Thanks!
Jenni

ANSWER: Hi Jenni,
Unfortunately a 10-gallon really isn't the best choice for goldfish. It's just really too small and you can't have more than 1 goldfish at most (when they reach maturity)

The best thing you could do is test your water for ammonia. Your tank may still be in its cycling stages and it won't be able to handle a lot of fish, let alone messy goldies. If the tank is still in its cycling phase then you'll need to be sure to not add anymore fish until it finishes cycling. But the bad thing is, if sticking to goldfish I wouldn't advise you to add anymore than the two comets you have right now. I've personally seen comet goldfish grow to 6 inches or more and two of them alone would be quite uncomfortable in a 10-gallon I know its hard to imagine now with them being tiny, but it can and does happen. If you dont want to give them away then they would probably be OK in the 10-gallon for a while but as they grew larger you'd need at least a minimum 30gallon tank to keep them both and maybe even larger if they keep growing.
Better yet a 55gallon would be the best size for them both, and you might be able to include 1-2 more goldies with them.

The problem with goldfish is you have to understand that they need large tanks and they cannot be kept with tropical fish. However, there are some fish they can be kept with but you must have a large enough tank on hand both to support the goldfishes bioload and size plus the tankmates.

If you are going tropical then you have a much easier ordeal on your hands. All you'd need to do is rehome your goldies, get an aquarium heater. First make sure your tank is cycled (as evident by ZERO readings of ammonia and nitrite) and then consider some of the many small colorful fish that are suitable for a 10-gallon. These include most smaller tetras like Lemon tetras, Neons, Cardinals, Black phantoms, glowlights, redfins,  Black neons, ect.. Plus Cherry barbs or Harlequin Rasboras, Dwarf gouramis, ottocinclus, shrimp, dwarf frogs, hatchet fish, guppies, bettas (only one per tank though) platies, ect...

It's also possible to have a cool-water aquarium with no heater, although if your house gets very cold in the wintertime, a heater set on low would be required to keep the temp in the upper 60's at least.
White Cloud mountain minnows are excellent candidates for a cool water aquarium. They originate from cold region of Asia and they look fantastic when kept in the proper conditions. They are also almost always available and quite hardy. They must be in schools of 6 or more. You could likely fit 6-8 in your 10-gallon with just a few other fish. Most platies and guppies are quite tolerant and can do well at cooler temperatures provided the temperature doesn't drop below say-68F. And both platies and guppies are hardy and colorful and provide lots of activity.
Hillstream loaches are another facinating little fish that can go in a cool-water tank. They are small little "pancake" like fish that spend their time grazing algae off the glass walls or just sitting there attached to the glass contently.

Just be sure to research any fish you are considering before you go out and buy them. Make sure you know their individual needs so you can be sure and provide for them correctly.

I really hope this helps!
Best wishes,
Karen~

---------- FOLLOW-UP ----------

QUESTION: Thanks Karen!
Unfortunately my last 2 goldfish died overnight.  I have had a tropical tank before so I think that's what I'll have to do.  I wonder what to do next then.  I'll have to put my heater in, and get the temp up.  Would I have to take out any water?  Those 5 little goldfish were only in the tank from Thursday evening to Saturday morning so I'm wondering if I could add more fish in that water.  What fish would you suggest I start with?
Also, I have quite a bit of exerience with male bettas but I was wondering if I could have more than one female in the tank.  
Thanks so much for all your help!
Jenni

Answer
Hi Jenni (You're welcome!)
I'm sorry to hear about your goldfish... :(

Before adding anymore fish, I'd do a large 50% water change and be sure gravel vacuum thorough just to get rid of what the little goldfish left behind. Some good cycling fish are Black skirt tetras, Zebra danios, or Platies.

You can usually keep female bettas together. But there are several things you should make sure about, read this helpful article for more info-
http://www.healthybetta.com/articles/New%20To%20Bettas/keepingfemalestogether.ht

Just be sure to cycle your tank first with a few fish and then only when the ammonia and nitrites are ZERO you can being to gradually start stocking it with a few fish per week.

I really hope this helps!
Happy fishkeeping!
Karen~