Cow and Lion?

How big is the tank?

They would be fine together, given that the cow was too big for the lion to eat, and that this is a big tank-180 or larger. In anything smaller, cows tend to bang into the glass and hurt themselves, and lions become very sedentary.
 
I wouldn't worry too much. Lionfish is a lot smarter than you think. Even if your cowfish were small enough to be eaten, lionfish simply wouldn't eat it because it knows cowfish is not the most delectable prey considering its horns and poisonous skin & organs, not to mention toxic mucus. Lionfish also has a faster growth rate than cowfish. So keep this mind when choosing the sizes of your potential fishes.
 
Actually, juvenile cow fish are well documented for annoying lion fish enough that the lion will suck them up--it just spits them back out right away. Starting with a larger cow will reduce the odds that the cow will nip at the lion.
 
it's fine i have kept mine together for months and the lion is bigger than the cow i dont think the lion bothers it coz he knows he will die if he takes a bite
 
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