as far as air-breathing fishes, there are many, and it doesn't get much better than Jeffrey Graham's Air-breathing fishes in terms of the account of such fishes. in terms of (distantly) related air-breathers, other fishes that fall into this category are the lungfishes, bichirs, bowfins, arapaimatidae (arapaimas and African bonytongues), old-world knife fishes, and onward through the teleosts--
--solomon
--solomon