I say negative on the seahorse cowfish combo....I had a five inch cowfish bite a chunk out of the head of a yellow seahorse....BTW to the folks that don't know about them, and just see them as the usually tiny little cute guys at the store......they get two feet long when full grown. Aside from a little armor, their only defense is their toxins. These fish can easily be caught by hand because they are so slow, and they need some defenses in the wild.....I have kept several over the years, and I don't think any toxins were ever released. The toxins are poisonous to the cowfish as well, so maybe that is why they hold off until really needed. Of course the oceans size will dilute it, and they can swim out of the toxins, but I would think this is VERY stressful to release the toxins and they aren't doing it unless in serious danger.....not an expert....just my experience.