Cardinalfish behavior

[rayadog]

Is this a dominance thing? First time I’ve seen this. Any insights would be appreciated. Caught a couple times in a few minutes and the jittery one would swim away a little.

 

[nautical_nathaniel]

Might be mating behavior, doesn't look too aggressive to me.

 

[Louis Z]

Spawning . If successful the male will stop eating while he holds eggs . They do seem to be a pair and any subsequent same species cardinalfish will be driven away from their territory . Brutally, I may add .