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Cuttlefish (specifically Sepia bandensis) compatibility with Tridacna clams?


Apr 24, 2007
So I just found this site and would love to keep a cuttlefish. I've seen them in the wild while diving and at aquariums. They are beautiful and interesting. So the question is, my other passion is Tridacna clams (specifically Tridacna maxima). Would a cuttlefish make a quick meal out of a clam?

Thanks a bunch,

What size were the cuttles and horses that you mixed (size of both)? This would give a me a nice option this year if the two would mix.
My cuttles were introduced into the main tank that at about 2-3 months. Aprrox 3/4" to 1".

First Id like to say that although I have found success with attempting tankmates with bandensis, there is not much other information available on this and there is always a chance that my experiences are isolated.

However, my methods and suggestions to introduce other animals into a sepia tank are the following.

-Have your bandensis settled into the main tank for a couple weeks before introducing new tankmates. This way, the bandensis have already taken on thier territories.

-Place a clear plastic breeder in the main tank where it is clearly visible to the bandensis.

-Place the new tankmate in the breeder and leave in here for a day or two so you can observe the bandensis behaviour.

-For the most part, look for signs of hostility like male flashing of aggression or actually striking at the breeder.

- If none are found, release the animal into the tank

I introduced seahorses about 3-4 inches. I saw no sign of aggression. Actually they didnt seem to even care. I never had problems with them for they outlived the cuttles when they died of old age.

I also introduced a yellow tang and a month later a blue tang. Bandensis showed curiosity, but no aggression at all. If anything, the yellow tang was more aggressive. The tang showed some territorial behaviours with the cuttles, but nothing that ever concerned me.

The blue tang never had any issues with the cuttles as they seemed to live harmoniously.

The clam was in the tank prior to the introduction of the cuttles and was never bothered. Unlike octos, cuttles dont seem interested in snails or clams. Even hermits seem to be uninteresting to them.
Thanks for the methodology behind your experience. I am getting my cuttle babies tomorrow and will be going through the struggle of getting them to a safe age before considering tank mates. In my case, the sea horses are the primary resident of the tank in mind and it is already well established. Additionally, the tank may be too large for the cuttles.

I have a juvenile gulf pipefish that is from a mating in my horse tank. I may try him (I think, still too young to be sure) in the cuttles tank at the 3 month mark and will use your intro method. In three months the pipe should be big enough to not appear as food and should be eating frozen mysis, hopefully, leaving the live feed to the cuttles.

Thanks again for the the info.
Just to clarify, My experiences and suggestions are in reference to Bandensis only. I have not tried this with Officianalis. I would expect an officianalis to not be so welcoming to other tankmates.

dwhatley-Good luck with the babies! That stage is the most difficult and nerve wracking. Watch out for cannibalism!

Good clarification but I fully understood which cuttles you were referencing.

Do you have any suggestions for what I can put in the breeder net to minimize the conflict while they are tiny? I have shells (one for each) and algae in with the baby mercatoris and, so far, they are successfully living together in a large breeder net but I don't expect the cuttles to use shells for a cubby. I use plastic plants with the mysis but am not sure if this really helps.

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