Now I was under the impression we already had a pinned article about this but bloozoo2 (thanks
) PM'd me and suggested I write up a list of possible inhabitants for your average peaceful 10 gallon community. That was almost a month ago and I've finaly got round to it - I hope it is of some use to someone out there as this is a common question.
What follows is a list of peaceful species that only get to about 1":
Pygmy cories (corydoras pygmeaus): There are several species of small cories but these are my favourite. They are also quite hardy and relatively common and, due to their small size, are an ideal cory for a small tank. Many people will keep larger cories in 10 gallons but this is not ideal due to their activity levels; with the pygmy species you don't need to worry about that. They should be kept in groups as, like other cories, they are shoalers. A group of 3-4 is adequate but the more the better. One thing of note is that, unlike your typical cory catfish, pygmies spend a lot of time in the lower middle layers rather than on the bottom.
Endler's livebearers (poecilia endleri or poecilia sp. or poecilia reticulata - which is actualy the guppy - depending on where you look): These are a livebearer very closely related to the guppy and quite easy to get hold of. They are hardier than guppies and smaller. Males are very strikingly colored with vibrant markings and unusualy-shaped tails with sword extensions and the like. Females are duller and look very similar to female guppies. If you are keeping them in a 10 gallon, it's best to stick to males only. For one, there's little point keeping females if you aren't breeding, secondly they are often harder to find and, lastly, and most importantly, endler's breed like rabbits and keeping a mixed group is not a good idea in a small tank. You quickly get over-run with fry. If you do end up with a mixed group, they should be kept at a ratio of 2 or more females per male to minimize the stress on the females. If, however, you go for males only, the number is of little importance and you could keep around 10 in a 10 gallon as they get to just about 1". Larger groups look most impressive.
Spotted rasboras (rasbora maculata): There are several species of small rasbora but this is probably one of the more common ones. Like most fish in its genus it is a schooler and does best in groups of 6 or more. A group of at least 4 would be ok though due to limmited space. Like many of the well-known rasboras, it will school very tightly if placed in a tank where it feels even slightly threatened or if its line of sight is always disrupred. They are more likely to stick together when kept in large groups in larger tanks though. Regardless, no community is truly complete without its schooling fish and this is one of the few that will do well in a very small tank. There are many other small rasboras, which also do well in small tanks, such as
trigonostigma/rasbora hengeli (which has several common names: Hengel's Rasbora, Glowlight Rasbora, Porkchop Rasbora, Slender Harlequin - demonstrating why you should use the scientific name for research
).
Myers' hatchetfish (carnegiella myersi): Another schooler, this is one of the smallest hatchetfish. Due to their unusual body shape, these fish make a very interesting addition to peaceful communities. Their only major drwaback is that they strictly occupy the upper layers so won't like to be kept with other top-dwelling fish. Though they are relatively hardy, they are prone to being bullied by anything remotely nippy so be careful with what you put in with them. Again, these need to be kept in groups but will do fine in a group of only 4 or so of their own kind.
Now to my favourite group, the gouramies. There are a surprising number of gouramies that will work and thrive in a 10 gallon but I've only listed the hardier and more common ones. Just so you know, bettas are also gouramies so all those betta species count here too (though I have not mentioned them in any more detail)
Sparkling gouramies (trichopsis pumilus): These are adorable and, unlike many other common gouramies, will spend more time in the middle layers rather than right at the top. They appreciate a well-planted aquarium and do best when kept as trios of 1 male and 2 females. These endeering little critters only get to about 1" and will even 'croak' or 'sing' when breeding or deciding territories. There are a few other trichopsis species out there including the common croaking gourami. Keep in mind that, though many stay small and are suitable, croakers are realy too big for a 10 gallon community and many of the others aren't as hardy either.
Honey gouramies (Colisa chuna or colisa sota - depending on how up-to-date your sources are): These are probably one of the most common gouramies and are often mis-identified or mis-labelled. Don't confuse them with the closely related dwarf gourami (
colisa lalia) which gets to 2" and, though suitable for a 10 gallon, is not ideal and far less hardy. Male honeys develop a lovely blue-black coloration on their underside when in breeding condition, which contrasts startalingly with their bright golden-yellow body color. Females are duller with a horizontal stripe running along their body but they make up for their lack of color by having a delicate appearnce that I always think is beautiful. These gouramies also preffer a planted tank and like to have floating plants to hide in. They also do best when kept as a trio. They get to 1.5" so are the largest fish I've listed here but they are still peaceful and would do well with anything else in the list except, perhaps, the hatchets as honeys preffer to stay in the upper layers as well.
Some suggested combinations (taken from another post of mine):
1 male honey gourami, 6 spotted rasboras, 4 pygmy cories
OR
3 sparkling gouramies, 4 myers' hatchetfish, 4 endler's livebearers.
OR
4 pygmy cories, 3 sparkling gouramies, 2 female honey gouramies
AND so on... you get the idea?
Whichever of the above fish you might consider, remember that you can keep a maximum of around 10 individuals (give or take a couple) but you should also remember that some need to be kept in specific size groups (which I have mentioned in all these cases). A lot of them can also be relatively tricky to find - but they are worth it as you can actualy make a community out of them in a way you can't with larger, but also more common, species of fish. Most LFS will order fish in for you or you can order online. Do make sure you fishless cycle the tank beforehand (read the links in my signature), take the time to research each species BEFORE you buy any and take any LFS advice with a grain (or two) of salt.
Besides the tiny, peaceful, community fish listed above, there are slightly larger fish (guppies, platies, neon tetras, otos etc) which also do well in smaller tanks. The purpose of this post, however, was to provide a short list of miniscule tropical species so please forgive me for not coming up with a comprehensive (and extremely long) list.
Just as an extra note, 10 gallon tanks need not be peaceful fish communities. Perhaps consider some shell-dwelling cichlids (
n. multifasciatus being ideal), a species tank of some of the more fragile gouramies (ie: licorice), a killifish breeding tank or a dwarf puffer tank. Even a heavily planted shrimp tank can look quite impressive. There's a multitude of options out there - you just need to do some research (try www.google.com
).
Can I ask a favour from everyone now? If you have good quality pictures of sparkling or honey gouramies, myer's hatchets, spotted rasboras or endler's livebearers, could you post them here please? I just think it would be nice to be able to see what they all look like
