Emerald Crab Giving Birth

trevorjosephsmith · Mar 30, 2020

Not sure how many of you have witnessed this but I thought I’d share! Last night I was having trouble sleeping so I woke up and looked at my aquarium with a flashlight in the dark. It was roughly midnight. My 1 emerald crab (there’s no other emeralds in the tank - I just bought her recently out of a group of 3) was standing on top of the rock, super straight, and opened the flap near her belly and was pulsing. Every time she pulsed, little crabs flew out and I could see them with the flashlight even better because it was dark. They were about as small as baby brine shrimp. It was the coolest thing I’ve witnessed in awhile, any thoughts? I’m going to feed little bits of algae pellets around the rock where they were released when the lights go out - my other crabs love it and I heard from someone else the baby emeralds will eat it too.

NB Reefer · Mar 30, 2020

That is amazing to hear. I have not witnessed this. I am sure many others have not as well. Too bad there is no video evidence...hahaha...

Softhammer · Mar 30, 2020

I too have had a mass larvae release of emeralds on a few occasions. I have about 10 of them. The chances of raising any is very slim though unless you have no pump driven filtration. They have a planktonic free swimming larval stage like almost all sea creatures. They float around for several days to weeks before they settle out of the water column. In an aquarium, unless you have a 100% dedicated system solely for larval rearing, the odds are pretty much zero. Those baby crabs make phenomenal food for anything we keep in tanks. They’re small enough that acropora can easily eat them.

Softhammer · Mar 30, 2020

They initially look like this and are very tiny before metamorphosing into a normal crab looking animal.

trevorjosephsmith · Mar 30, 2020

Softhammer said:
They initially look like this and are very tiny before metamorphosing into a normal crab looking animal.

They looked a lot like that. I only have two large sponge filters on the opposite side of the tank and the emerald crab was releasing its larvae in the low current side of the tank. Even if they were near the filter, do you think the sponge filters would still be safe for them?

trevorjosephsmith · Mar 30, 2020

trevorjosephsmith said:
They looked a lot like that. I only have two large sponge filters on the opposite side of the tank and the emerald crab was releasing its larvae in the low current side of the tank. Even if they were near the filter, do you think the sponge filters would still be safe for them?

I don’t have a powerhead either.

trevorjosephsmith · Mar 30, 2020

This is exactly what it looked like last night. If you look hard enough in the video you can see the little white baby crabs flying out of the flap

Softhammer · Mar 30, 2020

You may have a chance then. I’d say a sponge filter is about the only thing safe for them. Feeding and predation then becomes the issue.

trevorjosephsmith · Mar 30, 2020

Softhammer said:
You may have a chance then. I’d say a sponge filter is about the only thing safe for them. Feeding and predation then becomes the issue.

I only have 2 clownfish and the babies seem to be living in the rocks and get released at night when they’re sleeping so hopefully they have a chance, now I just have to figure out sprinkling the algae pellets where they live