The eggs that my first ovigerous female was carrying are finally in the process of hatching. There are some surprising and very fascinating things that I observed. Some of these things have never been reported before.
First, the eggs do not hatch pretty much all at once as with other shrimp. They hatch over several days.
Second, the larvae that hatch out of the eggs (always just a few at a time) are carried around by the mother under her abdominal area along with the unhatched eggs for a few days (1-3 days it seems). This is extremely unusual for a shrimp species, although this is the norm for crayfish, which carry all of their fully developed young around for a while.
Third, the larvae are already at a very advanced stage when they are free swimming. These are one of the most advanced free-swimming larvae that I am aware of in any shrimp. They are huge compared to the body size of the parents. The shrimp with the most advanced free swimming larvae that I was aware of up to this point was the American Freshwater Glass Shrimp (Palaemonetes paludosus), whose larvae hatch as *huge* head-down larvae and turn into post-larvae after only 3 larval stages. The larvae seem much larger in relation to their parents' size than even P. paludosus larvae.
Judging from the fact that it takes P. paludosus larvae only 7-8 days to develop into post-larvae (miniature shrimp), I would deduct that the Halocaridina rubra larvae also only need only a few days to develop into post-larvae (see below for more on that).
Fourth, the larvae have a huge body, which still looks like an egg. I am assuming that this body serves as a food-reserve until the larvae develop into post-larvae and start foraging for algae and other micro-food items. I am also assuming that the larvae do not eat at all and that the food reserve is all they have to develop into post-larvae. If this is true or not will have to be verified by further observation. It is not unusual for certain shrimp species to produce larvae that do not require any food until becoming benthic post-larvae. This is a major difference to Palaemonetes paludosus, whose larvae require food. Hence, it would seem logical to assume that the H. rubra larvae are at a higher stage of development than the P. paludosus larvae and probably need less time to develop into post-larvae than P. paludosus larvae who already have a very short larval time (about 1 week).
I will try to make some photos of the larvae if they get close enough to the front of their tank and will post them under the species description.
I will also write an article about these shrimp and their reproduction once the first post-larvae are running around and one whole reproductive cycle is completed, which should be soon. Mustafa
