Sally Lightfoot Crab: General Questions

[Chuck Anderson]

Dr. Ron,

I have a few questions regarding the Sally Lightfoot crab.

1. I have 2 Sally Lightfoot crabs in my 50gal. I believe one is male (large claws) and the other is female(small claws). For this type of crab, is sexing determined by claw size? If not, how are they sexed? Do these crabs reporduce in captivity?

2. I bought the s.l. crabs under the premise that they would eat and help erradicate some hair algae. What are their dietary preferences?

3. What is the ordinary lifespan for the s.l. crabs?

4. Are there any general guidelines for how many s.l. crabs can co-exist? And is there any kind of social order with these animals?

5. Is there any information (positive/negative) that the aquarist should be aware of before purchasing these animals?

TIA

[rshimek]

Originally posted by Chuck Anderson
1. I have 2 Sally Lightfoot crabs in my 50gal. I believe one is male (large claws) and the other is female(small claws). For this type of crab, is sexing determined by claw size? If not, how are they sexed? Do these crabs reporduce in captivity?

The large clawed one is probably male. To be sure catch them (snicker... :D ) and turn them on their back. The females abdomen (tucked under the main body will be wide, basically "U-Shaped." The males will be narrow, basically "V-Shaped."

2. I bought the s.l. crabs under the premise that they would eat and help erradicate some hair algae. What are their dietary preferences?

They appear to be omnivores when young, but do seem to eat a lot of algae. When they get sexually mature they may try to eat everything that moves, including any fish they can catch. If your male has large claws, I would say to start watching it closely. You will see it start to lunge for fish and such, and may want to remove it before it is successful.

3. What is the ordinary lifespan for the s.l. crabs?
I don't know. A guess, maybe 5 years.

4. Are there any general guidelines for how many s.l. crabs can co-exist? And is there any kind of social order with these animals?

I would suspect 2 males in a tank would fight. Don't know about females. In nature they are often found individually or in pairs under long-spined urchins. My guess is that they are not what one would call "social animals."

5. Is there any information (positive/negative) that the aquarist should be aware of before purchasing these animals?

See my answer to question 2 above...

Having had them and having had the males go aggressive, I would not like to have them in my system a second time.