Emerald crab vs Pitho crab

TCseh · Nov 13, 2023

I am having some bubble algae in my tank and I am looking for a way to manage it without any chemicals. I don't know much about pitho crabs but some people say they eat all algae and only sometimes pick at zoas. Emeralds I have heard can be hit and miss with the bubble algae and can sometimes pick at euphyllia.

Please give me your experience with these crabs and even other methods you have to deal with bubble algae.

I have a 50g display and only a bit of bubble algae around multiple frags. I plan on getting the crabs from reef cleaners.

Lavey29 · Nov 13, 2023

Pithos are great and reef safe. They love bubble algae but they set up shop in their little Rock house and don't venture far from there so you have to periodically hand place them where you want them to work for you.

TCseh · Nov 13, 2023

Lavey29 said:
Pithos are great and reef safe. They love bubble algae but they set up shop in their little Rock house and don't venture far from there so you have to periodically hand place them where you want them to work for you.

I don't have much bubble algae. Would he still set up shop in a place that he has eaten clean? I don't think he would starve but still. With that being the case would you recommend 2 with my size of tank? Again, I don't have much bubble algae but too much to hand clean.

Baronen · Nov 13, 2023

My pitho was insane. Would have been a great addition to a bigger tank but it was a 20 gallon with smaller fish. He would bury himself and have his eyes and claws out and try and capture fish as they swam by. I lost two fish while he was in the tank (not blaming the crab, possibility though). Amazing algae eater though

exnisstech · Nov 13, 2023

I just added a couple of pithos a few weeks ago in my reefer 170 (34g DT) . I already have a couple of emeralds in the same tank. The pithos are interesting. If they aren't eating they look like they are dead. More than once soon after I got them I was pulling them out to check. They have set up shop on the bottom against the rocks in the sand. I have seen them on the rocks eating but usually they are just laying on the sand looking dead lol. They have grown a lot in the short time I've had them so they are probably eating at night, its normally what the emeralds do. FWIW the emeralds had been doing well keeping bubble algae at bay and it only grows in the overflow wiers now. I got the pithos just to check them as I have heard emeralds can turn to coral and I wanted to be prepared tho my emeralds have been fine.
I only have male pithos. Females have the big defensive claws. Males just have the small food gathering claws. Information I gathered on the infonet.

kevgib67 · Nov 13, 2023

I never had pithos but decades ago I threw some emerald crabs in and they rid my tank of bubble algae. Never bothered my corals.

Lavey29 · Nov 13, 2023

TCseh said:
I don't have much bubble algae. Would he still set up shop in a place that he has eaten clean? I don't think he would starve but still. With that being the case would you recommend 2 with my size of tank? Again, I don't have much bubble algae but too much to hand clean.

They are scavengers and eat anything not just bubble algae but left over fish food scraps too. I have 2 in my tank which is similar size to yours.

Baronen · Nov 13, 2023

exnisstech said:
I just added a couple of pithos a few weeks ago in my reefer 170 (34g DT) . I already have a couple of emeralds in the same tank. The pithos are interesting. If they aren't eating they look like they are dead. More than once soon after I got them I was pulling them out to check. They have set up shop on the bottom against the rocks in the sand. I have seen them on the rocks eating but usually they are just laying on the sand looking dead lol. They have grown a lot in the short time I've had them so they are probably eating at night, its normally what the emeralds do. FWIW the emeralds had been doing well keeping bubble algae at bay and it only grows in the overflow wiers now. I got the pithos just to check them as I have heard emeralds can turn to coral and I wanted to be prepared tho my emeralds have been fine.
I only have male pithos. Females have the big defensive claws. Males just have the small food gathering claws. Information I gathered on the infonet.

Do yours burrow? Mine was a male as well but it was seriously cracked out. It looked like a Godzilla monster arriving from the depths every time it got out of the sand

TCseh · Nov 16, 2023

OK, I'll be purchasing 2 crabs by today. Either Pitho or emerald.

Any final comments to sell me on either one? Because after opening this thread it really hasn't helped me decide.

paragrouper · Nov 16, 2023

My emeralds (I have three) are all over the tank every day. They tend to knock the bubbles off and eat all the goodies underneath, so I’m cleaning loose bubbles off my intakes and the back of my power heads weekly. They are also quite acrobatic

Lavey29 · Nov 16, 2023

Pithos for the win

TCseh · Nov 16, 2023

Paragrouper and Lavey, stop making this harder for me please

Lavey29 · Nov 16, 2023

TCseh said:
Paragrouper and Lavey, stop making this harder for me please

I've tried both so just giving you my experience opinion.

Reefer911 · Nov 16, 2023

I had an emerald once, for like 10 seconds. He was too interested in my torch so to the sump he went.

I have a little bubble algae and decided I’m that I’m gonna go with a pithos

Lavey29 · Nov 16, 2023

I even have scarlet leg hermits that eat bubble algae but they don't seem to consume it. They deflate the bubbles though so I'm wondering if it will die off at that point too.

OctaviusBrine · Nov 16, 2023

I’ve had the zero luck with emeralds eating bubble I’ve tried atleast six of them. One ate two torch heads he was relocated. the newest seems to be nibbling on my birds nest. I have settled on just manual removal and balanced nutrients it seems to be working.