20 gallon tank ideas....

iamntbatman

Plenty of cover is a good idea with multiple caves. Rock piles and driftwood can be used for this purpose, and dense plants will be a help too. For apistos, it's usually best to have a trio of one male and two female fish. Be very careful about the sexes, as you will definitely run into problems with two males.

Here are some different options for small cichlids:

Rams - there are both the German blue and Bolivian rams. The Bolivian rams are hardier but get a little bigger. The German blues are often injected with hormones to "color up" but this results in most of the fish being male so getting a pair can be difficult. There are also different morphs of blue rams such as gold rams, long-finned varieties and even balloon rams. Avoid the balloons, as there are a lot of health issues involved with them.

Kribensis - Like the rams, they would do best as a pair rather than a trio. There are regular ol' kribs, but there are also plenty of more expensive species with different looks, including wild-caught specimens. Kribs are very hardy fish.

Apistogramma - Like I mentioned, a trio works best for these guys. There are tons of varieties with a huge range of prices. Some of the more expensive ones are some of the best looking freshwater fish, in my opinion.

Nannacara - Another type of dwarf cichlid from the Americas. Their care is similar to the apisto.

Shelldwellers - there are some shelldwellers from the African Rift Lakes that stay very small and would work in a 20g. Here's a site with articles on shelldwellers: Shelldweller corner

Jewel Cichlids - A little bigger than most of the others, with males getting between 10 and 15 cm. You could house a single fish or perhaps even a pair in a 20g, but you would be limited in the number of tankmates. They're West African riverine fish so their needs are similar to kribs, but they are also very hardy. They can be fairly aggressive.

Egyptian mouthbrooder - These Lake Victorian fish can be hard to come by but are are very cool. One male and two females would work well.

Badis badis - although not actually a cichlid (they're more closely related to gouramis) these fish behave similarly to dwarf cichlids. They can also be difficult to come by and often require live foods rather than prepared foods.

You could also house a single convict in the tank. A pair might also work but you'd be overrun with fry in no time.

kamazza

I think a lot of people stress too much about water quality. Water quality is important and some fish are more hardy than others but on a whole I think the more you fuss the more problems you will have, the same goes though if you dont pay any attention to the tank! All I do is use reverse osmosis and/or dechlorinated tap water dump it in the tank and thats it. My pH is around 7-8.5 which the rams will do fine at so I owuldnt call acidic water a requirement, more like they prefer acidic water. My rams have shown no signs of stress and have bred under the conditions ive described

okiemavis

I do want to point out the difference between water quality and parameters. Captive raised fish can usually adapt very well to reasonable ph levels. However, poor water quality (ammonia, nitrites, nitrates) isn't something any fish should be exposed to.

Also, many of these fish are fine with varying ph and hardness, but will require optimum levels for breeding. Even if you do not wish to raise young, their breeding behavior and colors are often incredible, and a wonderful facet of any fish. Rams are a pretty un-picky fish, and are quite easy to breed. Still very fun, pretty fish though!

Badis are quite cool. They can be tricky to find, but my LFS carries both Badis bengalensis and Badis badis on a regular basis, so they're defintiely out there, and importers are offering them for sale.

It'sJames

My new pairs of german rams have spawned in a ph of about 8-8.3. They're showing great color too.

tophat665

No no no no no. Soft water is generally acidic, and basic water is generally hard, but hardness is not pH. pH is a measure of the ratio of ionic hydrogen to ionic hydroxide in water. Hardness is two things, General Hardness, dGH or simply GH, which is a measure of the ionic Calcium in the water, and Temporary or Carbonate hardness (dKH or simply KH), a measure of bicarbonate ions.

Now there is a relationship between pH and GH. GH buffers acidity, so water with a high hardness reads with a higher pH. On the other hand, very soft water with no buffering capacity can be subject to pH crashes, where the water becomes very acid very quickly.

If you do a bit of research, you can probably come up with the relationship between hardness and pH to a much more precise level (I know it's possible to build a widget that will tell you the concentration of dissolved CO2 in your tank using the relationship between the hardness from a measured amount of baking soda in a small amount of distilled water and the pH drop CO2 causes).

So, Rams. German Blues like soft acid water, yup. Most fish from the Amazon basin are like that. That means either the water from your tap needs to be soft, or you'll need to mix RO water (which has no hardness) with a bit of your tap water (which probably has at least some) to get water they'll like.