Mystery spawning!!!! Am I a pappa????

[wseaton]

While taking a peek at my main 55gallon tank tonight with a flash light I noticed a swarm of what I first thought were small copepods, but then realized they weren't. These guys are about 1 1/2 -2 millimeters long, have orangish bodies, and swim backwards. Having bred and sold several species of freshwater fish, I'm almost positive the fry I'm looking at are indeed fish. They have two defined eyes, a tail, an egg sack, and swim in quick spurts backwards. But where did they come from? I've never had any two similiar species of fish in my tank.

The swarm was obviously eminating from the sand in a corner of my tank, and the little guys were taking to the free water as soon as they could. Copepods and other similiar beasties in my experience stay low, and these things do not look a thing like copepods nor any other sand crawler I've seen. They could, I guess be some type of shrimp, but I only have a large coral banded in my tank that soon caught on to the potential buffet and had to be beaten off with the siphon I was using.

I'm going to isolate the little guys and try to at least feed them. If they get bigger, I'll be able to identify them. What type of food though? Marine Snow...or similiar?

 

[BillyZ]

very intriuging! I've seen so many bizzare things come out my sand it's really hard to say. If they are in deed fry they could have come from something in your tank that was already pregnant when you added it to the tank. How long has your system been up and running? Have you made any recent additions in the last month or so? Even recent additions of LS or LR?

 

[wseaton]

Newest addition to my tank was a cardinal blenny added about a month ago. That's it for about 6 months.

I'm trying to get a closer view of these guys and try to determine what their tail looks like. Tail looks like it's horizontal, which would rule out a fish, but they're too small to tell 100%. Yeah, weird stuff comes in live rock all the time, but these guys clearly spawned from the sand well away from any rock.

They chase a flash light though, and make no attempt to hide.

 

[reefrunner69]

Sounds like mysis shrimp to me

 

[wseaton]

It's possible. These guys are either fish, or shrimp.

The bigger mystery is I've never added live mysis to my tank, so how could they spontaneously generate? Sand in this tank is almost a year old and was dry ooltic to begin with. Can mysis eggs survive dry bagging???

 

[reefrunner69]

Is there any LR in the tank?

 

[wseaton]

I finally got one of the little buggers under a magnifying glass, along with a really good detailed scientific sketch of a mysis.

Yep, look like mysis. I added a big piece of LR to complete a reef bridge, but that was several months and months ago. I take it their hatchings have some sort of seasonal thing, but it's strange they hatched several feet away from the newest rock.

Ah well, guess whos going to have a nice snack tonight when I get home from work??? 'ding' 'ding' 'ding'

Thanks for the tips my friends.