delusion of negation (nihilistic delusion) a depressive delusion that the self, part of the self, part of the body, other persons, or the whole world has ceased to exist. paranoid d's an older term for delusion of grandeur and delusion of persecution; its use is discouraged. delusion of persecution a delusion that one is being attacked, harassed, cheated, persecuted, or conspired against. It is one of the subtypes of delusional disorder.
Oto Catfish. These fish are perhaps the best kind of fish that you can get for the purposes of cleaning away algae from the plant matter in your fish tank. Their favorite type of algae to eat is brown algae, something that most other fish will stay away from.
1 Sponges: The omnivorous fish just like Angelfish feed on sponges. The sponges form the bulk of their diet.  Plankton: The plankton which includes different types of fish, shrimp, copepods, mysids and amphipods are a supplementary part of the diet of fish.