Self-contained "fuge" instead of sterile setup for prop

[eschaton]

Over the years, I've had an interest in saltwater fish breeding, but unlike freshwater fish, I've never really indulged. I've also had an interest in the possibilities of getting a lot of high-quality live rock and leaving it alone for a year or more, to see what develops. It strikes me these two might work together.

 

Basically, take a largish tank, and set it up with high-quality live rock, a deep sand bed, and powerful lights. Do not use any pumps, powerheads, or skimmers, only air-stones. Do not purposefully introduce anything to the tank for at least six months - and when you do, only introduce beneficial CUC members, ideally things like stomatella snails and asterina starfish which will reproduce in the tank. Dose the tank with rotifers periodically to get them established as well. I'd argue against putting macro into the tank, as I think it would cut down on the life suspended in the water column - just let nature take its course. Although the tank could be left for some time as a unfed, nearly self-sustaining system, at some point you'd probably want to introduce small amounts of powdered food in order to increase bio-activity in anticipation of fry.

 

Anyway, once you have a system packed to the gills with life, you could work out a transfer of the planktonic fry. Timing and method of removal vary considerably of course - in some cases (snails, clams, urchins) it might make sense to let the potential broodstock into the tank, as they wouldn't decimate the planktonic life. Others, like Shrimp and Bangaii Cardinals, it may make sense to introduce the egg laden/pregnant parent. And in cases moving the eggs alone could be helpful.

 

It's also possible to plumb such a system into a breeding tank - but in the reverse of the typical setup, with the breeding tank above the fuge.. The pump for the system would have to be external, and have its intake in the fuge covered with foam. During breeding, the drain to the fuge would have a small LED light placed over it, on order to attract fry to the overflow and down into the safety of the fuge.

 

I daresay that in such a system not every fry would grow to adulthood. Even if food concentrations were high enough, there will be incidental organisms like stinging hydroids which will get a few of them while planktonic. Still, such a system seems appealing because once set up it would allow grow-out with virtually no maintenance from the reefer - except routine water changes, and the hassle of getting the juvies out of the tank before they really decimated the pod population.

[BLoCkCliMbeR]

so this is a statement not a question right?

 

id argue against the air stones from the start. the make nasty salt creep, fast.

 

i have made a set up similar to what you have described, no sand bed, full LR only, macro.

 

and yes, it has the potential to teem with micro fauna. but i used airstones and it made a mess.

[eschaton]

so this is a statement not a question right?

 

id argue against the air stones from the start. the make nasty salt creep, fast.

 

i have made a set up similar to what you have described, no sand bed, full LR only, macro.

 

and yes, it has the potential to teem with micro fauna. but i used airstones and it made a mess.

 

Salt creep is ugly, but it doesn't hurt anything, and it takes quite a good deal of time for it to be enough to change your salinity. Just break off and mix back in deposits periodically. I'd say it's worth it given the alternative methods of agitation (pumps, powerheads) actively kill microfauna.

 

Edit: I should also say that while I typed airstone, I was actually thinking something more along the line of sponge filters (although the filtration wouldn't really be needed). I don't know if that would make a difference in salt creep - I used to run saltwater tanks with sponge filters and didn't see much.

[BLoCkCliMbeR]

ive done airstone, and "box filters " in that type of tank. it was my "refugee tank" and was subject to experimentation.

 

the salt creep would cloud the plexiglass lid. it was sealed to limit evap. it also can creep down to your equipment along the air lines and power cords. not good. sealing the tank with a good lid did help keep it down to a min.

 

im a big fan of the box filters for QT tanks etc. they are ugly, but can be run like a sponge filter with carbon.i ran air for the same reason, an attempt to make sure i didnt kill off my micro fauna. i ran air exclusively when i was trying to breed peppermint shrimp. when tuned to where you can count the bubbles it is a much more gentle way to move the water.

 

as far as NOT having macro in a tank like that, i would say the opposite. its beneficial to have it. not only is it a habitat for critters, but the fact that it cleans the water is a plus.

 

probably one of my favorite(10g) tanks to play in. never had any crazy out breaks, stability problems i got pics of it somewhere....

 

it was a 10g tank, air driven box filter, about 5lbs live rock, had chaetomorpha and polifera in it....later a 2'' sand bed. it always teemed with pods.

[absolon]

This sounds like a cool idea i think the reason its not done more is its not a method that would scale up well for large fish breeders. But it sounds like a much funner way to do it.

[eschaton]

as far as NOT having macro in a tank like that, i would say the opposite. its beneficial to have it. not only is it a habitat for critters, but the fact that it cleans the water is a plus.

 

I dunno. I would figure that if you need to have a stable population of micro-zooplankton, like rotifers, you'd need somewhat dirty, green water. A tank with lots of macro would still be swarming with copopods, but I'm pretty sure most newborn marine fry can't swallow something that big (with the exception of things like Bangaii Cardinals). Also, peppermint shrimp at least eat phyto, so you'll want green water to some degree.