Cone snails use separately evolved venoms for prey capture and defence. While 
most use a harpoon for prey capture, the Gastridium clade that includes the 
well-studied Conus geographus and Conus tulipa, have developed a net hunting 
strategy to catch fish. This unique feeding behaviour requires secretion of 
"nirvana cabal" peptides to dampen the escape response of targeted fish allowing 
for their capture directly by mouth. However, the active components of the 
nirvana cabal remain poorly defined. In this study, we evaluated the behavioural 
effects of likely nirvana cabal peptides on the teleost model, Danio rerio 
(zebrafish). Surprisingly, the conantokins (NMDA receptor antagonists) and/or 
conopressins (vasopressin receptor agonists and antagonists) found in C. 
geographus and C. tulipa venom failed to produce a nirvana cabal-like effect in 
zebrafish. In contrast, low concentrations of the non-competitive adrenoceptor 
antagonist ρ-TIA found in C. tulipa venom (EC50 = 190 nM) dramatically reduced 
the escape response of zebrafish larvae when added directly to aquarium water. 
ρ-TIA inhibited the zebrafish α1-adrenoceptor, confirming ρ-TIA has the 
potential to reverse the known stimulating effects of norepinephrine on fish 
behaviour. ρ-TIA may act alone and not as part of a cabal, since it did not 
synergise with conopressins and/or conantokins. This study highlights the 
importance of using ecologically relevant animal behaviour models to decipher 
the complex neurobiology underlying the prey capture and defensive strategies of 
cone snails.