I would increase number of cories and otos.
It is recommended that Corydorus habrosus should be kept in larger groups, 12 or more. They are actually midwater schooling fish (see info here: http://www.azgardens.com/p-825-cory-dwarf-cory-cat.aspx). Otos also are very social and like to be in larger groups in their natural environment. There was a very nice article about keeping and breading otos in last year TFH if you have access to the magazine.
I am just wondering why you would mix CPDs in this setup? Otos, corys and apistos/rams are all soft water South American fish and would make a beautiful tank without CPDs. CPDs come from Burma/ Myanmar and actually live in harder water and cooler temperatures. Also, 37G is a fairly small tank (my personal opinion), so rainbows may not be the best option because they need a lot of swimming space. They are from Australia mostly.
It is recommended that Corydorus habrosus should be kept in larger groups, 12 or more. They are actually midwater schooling fish (see info here: http://www.azgardens.com/p-825-cory-dwarf-cory-cat.aspx). Otos also are very social and like to be in larger groups in their natural environment. There was a very nice article about keeping and breading otos in last year TFH if you have access to the magazine.
I am just wondering why you would mix CPDs in this setup? Otos, corys and apistos/rams are all soft water South American fish and would make a beautiful tank without CPDs. CPDs come from Burma/ Myanmar and actually live in harder water and cooler temperatures. Also, 37G is a fairly small tank (my personal opinion), so rainbows may not be the best option because they need a lot of swimming space. They are from Australia mostly.
