Dojo loach question

[jenricae]

Can a Dojo loach be kept by itself in a community tank? Or should it be kept in pairs?

[Diana]

They are social, more is better. However, I have often kept them in 2s. They do not seem to be too aggressive.

Some Loaches are really domineering, and when kept with just one other fish of the same species the dominant one will harass the lower ranking fish, often to death. If you have a couple of easy going fish, especially in a large tank, then it is more likely that they will get along.
In a smaller tank the stress level is higher, and even a couple of easy going fish might bicker a little more than they would in a larger tank.

For Dojo Loaches, I would suggest a tank not smaller than 4' long (1.25 meters) then you could keep several (perhaps up to 5) and have a little room for some higher up swimmers.
In a smaller tank the social issues OR the waste load (or both) will build up too fast, and it is not so likely to work out.

If you are interested in this shape of fish, but have only a small tank, look into Kuhlie Loaches. You could keep half a dozen or so in a 20 gallon tank (long or standard shape) and have plenty of room for a school of small tank mates.