200 Litre Tank, Stocking Ideas Please Help

Even though it's 200 litres, the footprint is pretty similar to to my 125 litre. The dimensions will restrict you a bit compared to a standard shaped 200 litre. For cories, for example, stick to the smaller ones. And with just 80cm length, avoid fast swimming fish that need longer tanks. A good website to check with is seriously fish as it gives the minimum tank dimensions as well as volume; the only downside to this site is that it needs theup to date latin name in the search box and the names on here aren't necessarily the most up to date as taxonomists change fish names regularly.


How high is your pH, and how hard is your water? It is possible to have highish pH and soft water - my pH is 7.4/7.5 but my water is medium soft. This means I can keep cockatoo apistos no problem, and they breed in my tanks. It's fish like rams (not the bolivians, the other ones) that need soft water and low pH. Your list contains fish that prefer soft water (neons) and fish that like it hard (rainbows). Can I suggest you find out what your tap water is like - your water company's website should have the hardness on it somewhere. Once you know, that will give a better idea of what fish would be better in your tank.

Rummy noses (both true and false, they look very similar and shops often mix them up) will be fine
Neons - if your water is very hard, maybe not a good idea, but fine if it's softish
Bolivians - fine
Rainbows - dwarf rainbows (Melanotaenia praecox), threadfins and fish in the Pseudomugil genus would be fine. You might get away with Celebes rainbows. Most of the big, pretty rainbows need longer tanks than 80cm. They all prefer hard water.
Angels need at least a 100cm long tank, so I'm afraid they are not suitable.
Female bettas - fine. At least six. They form a heirarchy with a top fish and she maintains her position by aggressive behaviour towards the rest. With six or more, this aggression gets spread out among the others. Some individual females are as bad as males and cannot be kept with other bettas. If you ended up with one of this disposition you would need to separate her before she seriously injured or killed one of the others.
Cories - one of the smaller species as your tank's footprint is too small for the larger species. (small ones = Corydoras pygmaeus, C. habrosus, C. hastatus and C. panda)

There are not many fish that prefer a tall tank to a shallow one, the most obvious would be those fish that are 'tall' themselves, like angels. But angels prefer softer water and you say yours is very hard. Neons would also be unhappy in very hard water.

Having moderately soft water myself, I am not very familiar with fish that prefer hard water, apart from the obvious Rift Lake cichlids and most livebearers. But I knew I'd seen something somewhere and I've finally found it (note to self - make a note of it!)
Here is a link to an article on what fish like hard water. You'll need to research them to see what would be suitable for an 80cm long tank, but it will give you a starting point.
A few other fish to add to that article are lemon tetras, red eye tetras and false penguin tetras (Thayeria boehlkei, the fish profiles on here call it just the penguin tetra, no mention of the false bit)).



The other thing to bear in mind with a tank this shape is that you should have fewer fish than a standard shaped 200 litre because the surface area, where gas exchange occurs, is smaller. With filters circulating the water this isn't the problem it used to be decades ago, but tall thin tanks should still be stocked a bit lighter.