Droob

 

Rayger

 

Skimm

 

Filterfin

Slithsac

Slithsac are very similar to Terran snakes.  There are quite a few differences though.  Slilthsacs have a set of quills on the back of their head.  When threatened, the creature coils up, leaving the quills exposed, facing upwards.  It can then stand these quills up, similar to a porcupine to fend off an attack.  Slithsacs also have a set of flaps of skin along their body that they can fill with air to make themselves seem larger.  These adaptions are all defensive as Slithsacs are quite docile.

Arsetic

Mudlurch

Dromb

Dromb have a tough, leathery body, but an exposed fleshy head.  It will often float vertically, face out of the water.  The fleshy head has cells similar to that of plants, and the fish is able to photosynthesize the nourishment it needs.  Its tough body helps protect the fairly defenseless fish during this process.