Crab

noahclay82 · Mar 31, 2022

Will Emerald crabs Harm fish at all?

jda · Mar 31, 2022

Not if you keep them fed. They are algae eaters and scavengers by heart. However, if you starve them, they will eat coral and try and catch fish... and so would you.

They just cannot eat fish poop all of the time. I have a large population of emeralds, peppermints and hermits and I make sure that some food escapes into the rocks and stuff every time that I feed. This keeps them behaving well and doing their other jobs of eating algae and aptasia and stuf.

noahclay82 · Mar 31, 2022

jda said:
Not if you keep them fed. They are algae eaters and scavengers by heart. However, if you starve them, they will eat coral and try and catch fish... and so would you.

They just cannot eat fish poop all of the time. I have a large population of emeralds, peppermints and hermits and I make sure that some food escapes into the rocks and stuff every time that I feed. This keeps them behaving well and doing their other jobs of eating algae and aptasia and stuf.

Will they eat brown algae I have a ton of that in my tank

Sharkbait19 · Mar 31, 2022

If you mean diatoms by brown algae, they won’t do too much for that the way a snail would. Emeralds are more for hair and bubble algae (which they are amazing at). They are harmless to any fish except a sick and dying one. Snails, hermits, brittle stars, and coral can be at risk depending on how well you feed it and if you wind up with a bad tempered one.

Anemone_Fanatic · Mar 31, 2022

My emeralds have been harmless so far. Just give them nori when the algae starts to run out, and your corals and fish will probably be fine.

jda · Mar 31, 2022

Emeralds will eat real algae. They don't seem to want to touch diatoms, dinos or cyano. They don't eat a ton of it, but they can get their claws into nooks and crannies that snails, urchins or fish cannot reach. They are helpful.

rmorris_14 · Mar 31, 2022

I've seen my emerald swipe at my fish usually during feeding time. It doesn't strike me as intent to do harm. More like a grumpy old man waving his fist at kids on his lawn.

I also make sure he gets some of the frozen food a couple times a week as well to keep him well fed.

shakacuz · Mar 31, 2022

i have 2 pitho, and 2 emerald crabs in my 40B. i make sure when i feed frozen to give them a piece individually whenever i can find them. otherwise, when i broadcast feed i make sure some food gets in the cracks/caves/crevices in rocks as @jda mentioned.

jda · Mar 31, 2022

Just to reiterate, nearly all of the posts that you see about emeralds, shrimp, hermits or the other reef safe inverts eating fish or corals is usually due to them starving. Keep them fed and they will do their jobs well. I feed flake a time a day just for this since it gets everywhere.

Crabs and shrimp need elements to molt correctly - make sure that you are changing water or otherwise supplementing a WIDE swath of elements.

Lastly, they all seem to live about three years if you get them small, so they do need to be replaced every now and then.