Sometimes routine tank maintenance isn't so routine. The 75g Tang tank was due today to get 1/2 the rock work and decorations removed so I could thoroughly vacuum the sand. I removed everything on the left side of the tank except for some shells that a pair of my Telmatochromis sp. "temporalis shell" had grown fond of over the past few weeks.
If you have experience with shell dwelling cichlids with a sand substrate, you'll know that they will often fill unused shells with sand and even bury the shells completely. I suspect there are at least a couple of reasons for this. One, open shells in proximity to the shell being used by a breeding pair are an invitation for competing shell dwellers to set up shop nearby. Two, open, unburied shells nearby provide hiding places for small predators intent on ambush.
In any case, I began moving the shells out of the way and noticed that one was pretty empty of sand. I decided to basically just move it instead of upturning it. So the other shells seemed to be at least partially filled with sand. I started dumping them because detritus will often collect in them if they aren't being used. As a little sand came out of one of the shells I also noticed some darker colored objects dropping out - WIGGLERS! Crap! Technically, they're probably past the wiggler stage, but I still consider them wigglers because it doesn't appear they can do more than scoot across the sand. They're certainly not swimming about in and out of the shell.
I put the shell back down expecting mom to come get her brood and put them back. I moved away from the tank and just waited for a few minutes. Sure enough, here she came. She moved over from some nearby rocks, assessed the situation and, very methodically, began picking them up and moving them back into the shell. I did't count the wigglers but I figure there at least 8-10 that came out when I first noticed them. I waited until she had completed the task before I moved the shell to the corner of the tank.
Where the shells had been originally was not an ideal spot to attempt to raise some fry. The shells weren't very strategically placed to defend properly. Putting the shell in the corner and rearranging the rock nearby offered three things, 1) additional protection, 2) a well-defined and defendable territory, and 3) an increased probability of future breeding success for the pair.
In the top photo above, you can see the female peeking out. It's hard to tell, but the shell is only about 10" from the camera. The shell she's in is about 7" from the aquarium glass. She is quite aware of my presence, and I had to be real still for a a minute or two before she would come out. Even then, it was only for a couple of seconds to do some house-cleaning. The wigglers are deep in the shell. I didn't take any photos of them because I was too intent on getting them back in the shell before they were "seen" by other fish in the tank. It would be naive to think that, just because they might not be seen, other fish weren't aware of their presence. Fish give off multiple cues about their presence - audible, visual, and chemical.
In the bottom photo above, you can see the male with the noticeable nuchal hump. At about 3", he is significantly larger than the female, who is probably about 2/3 his size at 2" and less full-bodied. Yes, they are as black in person as they are in the photos. The are in fact jet black in color. Below are a couple of closer shots I took with the shells moved into the corner of the tank.
The Cichlid Room Companion
Tropical Fish Hobbyist
American Cichlid Assoc.
African Cichlid Hub