There are some fish that are not large that I think are monsters because of the way they feed, pike-heads, leaffish, piranha, pike-top minnows, cachorro, gulper cats, phagos, and candiru are some of these. There are others that are monsters due to there appearance, eels, threadfin paradise fish, grenadier anchovies, chacas, are all in that group. Then there are the gentle giants like tors, aussie lungs, rays, and meglobramas. Too me these all count as monsters.