From 2speccers2tools wiki

To be fair, sometimes stuff just goes really badly. The Nomsalps are a strangely inverted form of the Wetnom, they still have three hearts, one acting as a circulatory system and also for salt disposal, another working as a stomach, and the third providing thrust and booting out the wastewater. Nomsalps occurred when a wetnom spore got its genome in a real twist because of some generic radfauna’s irradiation and probably resembled the tunicate-like form on the bottom right, attached to the seabed with a lump and limited roots and overall stunted, it persevered though, and so did other individuals that got blasted with radiation, they were all a little different, yes, but this was an advantage. If your genome is crippled it could help to have diversity. While most ended up breeding back into the wetnom population, some split off further and radiated into the myriad of forms called Nomsalps. Despite their name, nomsalps are not exclusively pelagic and can even be found in freshwater habitats, like their ancestors they have a stomach lining inhabited by a species of Nuclear sunscreen poopycell to avoid genetic damage to adults, the young of course lack this protection and are more selective feeders, not indiscriminately pulling in water but rather plucking specific morsels out with small inhalations. While most of these ‘larvae’ will continue to feed and grow here, other’s callings lay on debris, on rocks, in reefs, and in soft substrates, many species have different ways to adhere to a home, either physically or chemically. Adults of most species are indeed fecund and seasonally produce a sporophore to their side which churns out millions of spores daily for a short while, which fuse with spores from other individuals and then begin development. Most nomsalps are dull greyish-blue colors, allowing both photosynthesis and some camouflage. However, the nonphotosynthetic species use an array of pigments like carotenoids and iridilides to create a spectrum of colors ranging practically the whole rainbow (and yes, even beyond!), these are however mostly sessile species that need a constant influx of small foods to survive, particularly those in shallow water environments. Most are more moderate in their required intake of food and can go a few days, some species (mostly those previously in the obsolete subgenus ‘microstoma’) do not technically require food either and can survive wholly on photosynthesis still, this is especially common in freshwater species as particle counts in some areas can be atrociously low. Some species have regained simple floats (analogous to their ancestor’s buoyancy organ) and spend their lives at the surface of the ocean, or living a life nearly identical to their ancestor’s but on hard substrates like rocks rather than emerging from the sediment.

A comparison of homologous parts between a wetnom and a Nomsalp.
A pelagic species of Nomsalp.