ID Request

[DKoKoMan]

I am wondering if anyone has or has had these either in their sump or DT. I found them in my sump, the swim in a pulsing manner and will sometimes stick on the glass or return pump. I have done some searching and have come up with no photographs or information on these.

[DKoKoMan]

I should add that I have seeded my DT and Sump with 2 bottles of Copepods from Big Al's.

[Myka]

It appears to probably be a trochophore or a veliger which is part of the larval stage of many critters like some snails, abalones, molluscs, urchins, etc. Trochophores and veligers may look much different from one species to the next. Here is the Abalone Life Cycle for example:

[DKoKoMan]

I hope that's what it is and not a pest as I looked tonight and there was approximately 5-10 more.

[Myka]

Originally Posted by DKoKoMan

I hope that's what it is and not a pest as I looked tonight and there was approximately 5-10 more.

Not likely at all. After the veliger stage, it takes most animals several weeks before they will metamorphose, and this usually takes more than one ecological, biological, or nutritional trigger. I wouldn't be concerned. You could squish or siphon them out if you are concerned though, or just brush them off, and they'll get filtered out or eaten.

You do hear of the life cycle completing, but usually in commercial systems where there may be huge refugium-type vats where it's possible for a larva to go through the entire life cycle without being filtered out or eaten. Not all snails, clams, etc will have such a long or complicated larval stage, it really varies from one species to another and the ones with shorter life cycles are the ones we see reproducing in our reef tanks, such as Collonista snails.

If you care to nerd out, here's a link to a clam life cycle for example. http://www.advancedaquarist.com/2009/8/inverts

[DKoKoMan]

Once again, thanks for all the information! I knew posting on here would give me some answers.

[Myka]

You're welcome.

[monocus]

what they are are Cassiopeia,upside down jellyfish.i use to get them in the hundreds-basically harmless.i figured i was getting them from my brine shrimp eggs

[Myka]

Originally Posted by monocus

what they are are Cassiopeia,upside down jellyfish.i use to get them in the hundreds-basically harmless.i figured i was getting them from my brine shrimp eggs

I'm pretty sure what you're thinking of is hydroids, which are a very common contaminant in Brine Shrimp eggs, and have a medusa (larva) stage that resembles jellyfish. Unless the OP has adult Upside Down Jellyfish in his tank, the odds of these being larva from said species is extremely slim.

[monocus]

nope.i actually raised them till they were over 2 inches wide,from the photos,they are upside down jellies