Once upon a time, the standard advice from advanced hobbyist to the novice was bigger is better. Buy the biggest tank you afford. But then came the birth of the nano and pico tank/desktop tank hobby, and suddenly 10 gallons wasn't so small. With better filter technology and attention being brought on smaller species of fish, you've got so much to choose from.


First, consider if you like fish that school (eg. tetras and danios), pairs (dwarf cichlids), or aggressive/semiaggressive (barbs, dwarf gouramis).

Freshwater suggestions:

• Shoal of 9-12 zebra danios - under-rated hardiness (will survive cycling...heck will survive chlorine- wouldn't recommend it), graceful and cheap (they form amazing tight shoals)
• Shoal of 6-9 threadfin rainbows - gorgeous fish and one of my all time favorites - people will flock to see it, can be touchy
• Shoal of 6-9 P. furcata "forktail blue eyes" - bright yellow fins, they look like birds. Keep them in a dark bottom tank
• Shoal of the "ubiquitous" cardinal tetra 12- try a tank with the back and sides painted black, bare bottom with some black rocks at the bottom, a light with blue in the spectrum- "jaw dropping" make sure you have a good heater 78'-80'
• Any of the dwarf cichlids - tetras make good dither fish and most of them are found in soft water like the dwarfs/apistos
• Carinotetraodon travancorius (Dwarf puffer)- freshwater planted tank, 5-6 in this size tank, best to keep them in soft water , feed snails. They become very tame.

Brackish/salt added suggestions:

• Neovespicula depressifrons (aka dusky goby- not really a goby, leaf goblin fish) - these have to be one of the coolest micro predetor fish. They reach 3-4 inches. WARNING: VENEMOUS SPINES- it's like a cross between a grouper and a lionfish - you could probably house up to 4-5 in a ten gallon
• Peacock Gudgeons- very beautiful fish, looks like a goby- not a goby. 3 pairs possible in a 10 gallon
• Bumble bee gobies- Note: some are brackish some are not they all look pretty similar
• Micropoecilia (all the dwarf wild guppies ), Gambusia (look for the Hollbrooki- spotted variety - they look like miniature dalmation mollies)

Saltwater:
*tip- filter should have 10-15x turnover rate, be ready to clean salt off of everything

• Clown gobies- if you plan on keeping more than one of the same species, I suggest a lot of hiding spaces and get at least 4 of the same species. They can get aggressive.
• Hover goby- real cool fish- they are a tad aggressive. only keep one
• Dotty backs- aggressive- go with only one and add after you've added the rest
• Fire fish/Dart fire fish- peaceful and pretty - try a pair

I hope that gives you some ideas