This is a double post from the Random Pic of the Day thread but just need to memorialize this here as well.
As I posted above awhile back, a couple of weeks ago one of my lettuce sea slugs laid eggs. I thought no way in hell any would survive. I didn’t even know they were viable until it laid a second clutch & I looked at them under the microscope and saw them wriggling around. Honestly I thought the slug was dying & laying unfertilized eggs because that is a documented behavior & sea slugs can be delicate.
Then this morning I get home from a haircut and see a little blob floating around the tank. I see one of the fish try to eat it and then spit it out. Thought maybe it was a small snail. Took a closer look, and sure enough… It’s a baby sea slug! Immediately grabbed a little plastic cup and netted it out to get a better look at it. Then I keep looking and find a second one right at the waterline. There must be dozens more. This hobby is so f’ing cool!
I have a feeling I’m gonna be seeing quite a few of these guys popping up in the next few days & weeks. Apparently the planktonic stage is by far the hardest to survive, and once they go benthic their viability is pretty good. Fingers crossed. Now wtf am I going to do with all these sea slugs?!
For what it's worth, I have found several more this afternoon, all crawling around on a few different Penicillus macroalgae. I'm gonna say it's safe to say that Penicillus is their food source as juveniles and adults, but I have no idea what they survived on as veligers.
This one was crawling around on some Penicillus when one of the adult slugs came to graze, and the juvenile crawled around on the adult before going back to the algae.
Here’s another shot of one of the baby sea slugs. I have counted about 5-6 of them so far that I keep track of on a daily basis. They mostly stay on macro algae, but this one ventured onto the glass today. (This is a view from underneath.) A couple are also hanging out on the roots of a mangrove propagule I have suspended in the tank, but they’re too far from the glass to get a good pic of them in focus.
For reference, this guy is about 2-3mm long. The largest is about 5mm long, so they’re quite tiny.
Thought some may find these photos interesting. One of the adult sea slugs seems to be ingesting red algae and incorporating it into its tissue. Im no biologist, but according to Google apparently in addition to chlorophyll, red algae photosynthesize using another pigment called phycoerythrin. So it seems (and of course this is purely anecdotal) lettuce sea slugs may have the ability to incorporate phycoerythrin via kleptoplasty.
Fourth clutch of eggs laid today, and also noticed a VERY tiny baby slug on the glass. Way smaller than the others, so this guy must be from the second or third clutch of eggs that was laid. Based on timeline I’m guessing from the second clutch.
