Please welcome back Frank Indiviglio to That Fish Blog. Frank gives his unique perspective on another interesting, sometimes aquarium inhabitant, the crayfish.
Freshwater crayfish, found on all continents except Africa and Antarctica (the southeastern United States, home to 80% of the world’s species, is a hotspot of crayfish diversity), are often purchased as an “oddity” or scavenger to add to the aquarium. However, these active Crustaceans make fascinating pets in their own right and are well worth more attention. I will write more about the specifics of crayfish care in future articles, but would now like to recount my experience with the maternal instincts of one species, the red swamp crayfish, Procambarus clarkii.
It is difficult to house crayfish in groups, as they tend to consume tank-mates that have recently molted (newly-molted crayfish are soft and defenseless). I was, therefore, fortunate in having the opportunity to observe a female with her young in an aquarium. I came across her while she was traveling overland (they do this on occasion) between ponds at the Prospect Park Zoo in NYC. In typical crayfish fashion, several dozen young clung to the swimmerets (feathery organs) on her underside. (Note: the red swamp crayfish is native to the southeastern USA but widely introduced elsewhere. Non-native crayfish cause serious problems in many parts of the world – please do not release unwanted pet crayfish).
Established in a 5 gallon aquarium, the female soon became quite bold and allowed me a peek at her version of maternal care. Any disturbance caused her to rear up, claws extended towards the threat – she definitely seemed more aggressive than crayfish I had kept in the past. The young remained on the swimmerets for over two weeks and then began making short feeding forays on their own but, to my surprise, returned unerringly to their mother after eating. At this point they also began to scamper about the rest of her body, sometimes covering most of her head from view. Knowing of this creature’s pugnacious disposition, I wondered when her “patience” would reach its limit. That limit came after about three weeks, when she promptly began devouring the prodigy she had so carefully nurtured until then. The survivors took refuge in the hiding spots (cracked clay flower pots) that I had provided for them, after which I moved the group to a larger aquarium.
A number of crayfish species are readily available and do well in aquariums. Particularly interesting are stream-dwelling forms, such as the red-tip crayfish, Orconectes erichsonianus, which seem determined to re-arrange every stone in their tank in an effort to establish the perfect home. Others you might consider are the P. alleni, a blue strain of which has been developed for the pet trade, dwarf species such as O. compressus, and the bright blue Australian yabbie, Cherax quadricarinatus.
I’ll write again soon and highlight other species. Until then, I’d appreciate hearing about your own experiences.
A good deal of interesting information, including a key to help you identify the crayfish you may come across, is sponsored by the Carnegie Museum of Natural History:
Thank you, Frank.
I was excited to get your reply. I first heard about raising crawfish at a regional ag teacher conference this past summer. A teacher from the North East raises them and emailed a few ideas, but didn’t give a lot of details. The 500-gallon tank I have to raise them in was once a tilapia tank, but students hate the smell and waste created by them and I ended up being the one to clean the filters. So, the tank has been idle for about 6 years. I must also tell you that the tank is located in a greenhouse. Temperature is easily regulated, but it will get warmer in May. Our school is totally IPM, so no pesticides are used in the greenhouse, either. Some of the main goals of raising the crawfish were to see the development of them through the molting process, to learn water quality by raising aquatic animals, teaching responsibility and to integrate math, as well as some reading and research methods. Lastly, if possible, to have a small “luncheon” at the end of May and enjoy the product that was raised. I went crawfishing in the creek last summer and steamed my catch….what delicious lunch! How many high schoolers could say they did that? Any help or suggestions you can give is certainly appreciated.
Hello Dianna, Frank Indiviglio here.
Thanks for the feedback. Sounds like a wonderful plan on all levels.
I suggest the Red Swamp Crayfish, Procambarus clarkii; This Commercial Rearing info is good background reading. They are large enough so that eggs and hatchlings are easily seen, and spend a good deal of time with maternal care; fairly hardy re water quality and can the warm and slowly fluctuating temperatures you mention.
Thank you Frank, for the information. Once school begins after the break, I intend to begin preparing the tank for the crawfish. What type of filtering system do you suggest? I will read the information you suggested in the mean time.
My pleasure; I’m glad the information was useful.
If you still have the system that was used for the Tilapia, we may be able to work with that – if so, please send details. Otherwise I’ll suggest other options.
Enjoy your vacation and a happy and healthy New Year to you and yours,