The largest, most ancient, and scarcest of the giant fish is the Mutable Halfen (MH). MH is among a sparse few species that lives long enough to be classified as unending, despite this and against a great number of other odds it nowhere near classifies as sentient, in fact the only reason it seems to have lived so long is its incredible internal processes. Unlike most creatures, even multiforms, MH can reconstruct their biological processes in order to meet their physical needs, along with this they can physically shed various organs and even alter their brain structure up to a point. While the vast majority of the MH (22) are over 500 meters long 2 additional MH have been found being less than 20 meters, due to their feeding conditions. On feeding conditions there is a bounty to relay, while the MH are generally filter feeders, they can alter this too, and it seems the smaller they get the more prone to hunting other creatures they get, hence the fact that the 2 micro-MH are some of the most vicious predators on the planet, tearing through species 5 times their size, and consuming them in less time than the kill itself took. They also seem to take on a level of photosynthesis at larger sizes with 3 of the MH floating only 10 meters under the surface, while still filter feeding it seems to nicely supplement their diet, and with a bit of trepidation the exobiologists tasked with MH's study have admitted it seems to take pleasure in this. It should be noted before we finish with the MH, although there are currently 24 properly classified MH, as we don't know how they breed we have identified a further 7 masses which may or may not be MH children.