Gastrocyathus gracilis is commonly referred to as Slender clingfish . Difficulty in the aquarium: There are no reports available yet that this animal has already been kept in captivity successfully. Toxicity: Toxic hazard unknown.
The Slender clingfish is endemic to New Zealand, where ist is found amongst weed at low tide, and on brown algae in the subtidal zone.
Gastrocyathus gracilis appears to be restricted to algal species with strap-like fronds, where the feeds mainly on harpacticoid copepods.