please help identify a shrimp and a flatworm

[markush]

Sorry for the bad shrimp pic they moved fast and i don't have a true macro lens.

This was taken one night when i noticed a ton of little creatures flowing with the current...they had to have just hatched. I have two pepermint shrimp, a male and female and mama had eggs in her when i got them so my best guess is this is a peppermint. Can anyone confirm that?

The flatworm came with my live rock which is from the Gulf of Mexico near Tampa Bay Florida. Anyone familier with it or have an exact name for it? I'm curious if i should start to be worried because i've seen about a half dozen of these in my 90 galllon. This ones about an inch and a half long in this pic. Four have been about a third this size.

[greenbean36191]

The shrimp is a larval shrimp, but at this point you can't get much beyond that. They pretty much all look that way at that age. If it is a pepermint shrimp, it's extremely unlikely that it came from the others you have. Their larvae are so delicate in the early stages that they're fairly tough to raise even in specially designed tanks. A reef tank is too dangerous for them to develop.

The worm is a polyclad flatworm. They're predators and the ones with the same general coloration as yours tend to feed on mollusks like snails and clams.

[Ninong]

Hi markush,

I have two pepermint shrimp, a male and female and mama had eggs in her when i got them...

Peppermint shrimp (Lysmata wurdemanni) are simultaneous hermaphrodites, as are all shrimp in the Lysmata genus. There are no separate males and females.

The eggs that you saw were actually attached to the shrimp's pleopods. After the larvae hatch from the mature eggs, the shrimp will molt its exoskeleton. It is during this soft-shelled phase that it is receptive to receiving a sperm packet from another L. wurdemanni shrimp that is in the hard-shelled phase. The "male" phase shrimp will grab the soft "female" phase shrimp and make contact with it crossways from underneath. The sperm packet can remain viable for weeks and can be used for more than one reproductive cycle. Thus it's possible to buy a single Lysmata shrimp and have it experience two or three reproductive cycles with fertile eggs even though there are no other shrimp in your tank.

In your case, since you have two individuals, they will synchronize their reproductive cycles to maximize the mating opportunities. The "male" phase shrimp will be carrying immature eggs attached to its pleopods when it transfers a sperm packet to the "female" phase shrimp. The "female" phase is very brief, lasting no more than a few hours.

It is also during the "female" phase shortly after molting that the shrimp is most vulnerable to attack. This is not likely to be a problem if you have two shrimp of the same species but cannibalsim can be a problem if you keep too many shrimp in the same tank or if you keep an aggressive species, such as Stenopus hispidus, in a tank with Lysmata spp. The freshly molted shrimp will seek out a hiding place to wait out the hardening of its exoskeleton if there are predators in the tank. BTW, Stenopus hispidus is not hermaphroditic. They have separate males and females and it is very important that you not acquire two males because they will literally tear each other limb from limb until only one remains alive. This is not a problem with Lysmata wurdemanni as any two will form a "pair."