new idea, possible way to raise fry?

[Chad Vossen]

i gave raising damsel fry a chance, they would keep dieing from ammonia!
then i came up with the bright idea of using a coffie filter (paper) and containing the fry within the filtered area with water dripping into it. this worked very well since i had the fry in my sump, but i killed my rotifers when trying to add them!

well, iv done some thinking, and threw together a quick drawing. this whole idea is based on the theory that rotifers will not be able to pass through the plastic mesh, and that flow will be low enough they can escape the filters.

heres my quick drawing:

i think this could be plumbed into a reef tank which the fry hatched in, simply move the fry into this tank. i think 5-20 gph running through this tank would be enough to keep ammonia from building up. then i think the divider will have enough filters to keep the "suction" from trapping the fry and rotifers.

i came up with the question "what will feed the rotifers?". maybe some phytoplankton constantly being dripped slowly into the tank would allow the rotifers to be fed, which feed the fry and any phyto that passes through the filters just goes on to feed your pods and inverts in the system.


what do you think? is this worth looking into?

 

[mwp]

Chad, A lot of folks think about this. For larval rearing, I could definitely see it being a possible solution. For long term growout, not a chance...too much waste is produced (see Wilkerson's book for her experience with a grow-out system plumbed into a broodstock tank - the jist, grow out heavily polluted the larger tank).

Definitely couldn't apply greenwater techniques with a setup like this...phyto would get blown out way too quickly to be of any real value (from a larval hunting standpoint).

Worth trying but be prepared to modify or DISCONNECT

Matt

 

[Chad Vossen]

lets just say the established system is 100 gallons, and 60+ lbs live rock, 30 gallons of the 100 is dedicated to refuge.

if the fry are producing that much waste to polute a growout system, how do they not kill themselves in a small tank, granted they get water changes. or what if i chose to just raise a portion of the fry, maybe 20?

i really do need to read that book

 

[Dman]

The other problem, I know I've tried it, is that the coffee filters plug up real fast, swapping them out is a PITA and if you miss the boat on changing them, you have a floor that's really, really wet.

 

[Chad Vossen]

someday i will make an attempt at this. i think the filters can be kept clean fairly easily, and that if i build the divider right, switching them wont be to much trouble. the most problems i can see is the difficulty of keeping rotifers healthy and well fed once in the tank.

 

[Chad Vossen]

also, i tried to show it in the picture, but the divider will be lowered so that incase the filters get cloged, the water can go up and over the divider.

 

[David M]

Your drawing is very much like my larval tanks but forget the coffee filters, just make the divider out of <50um mesh screen and the rotifers will stay on the larvae side. Leave it "stand alone", forget the connection to the reef. This has been discussed at length here, there is NO advantage and MANY potential disadvantages, what's the point? You can filter the back side of the tank any way you want, I place seasoned bio-balls back there after met.

 

[mwp]

BTW, Prime and Water changes will keep the ammonia in check (if it was truly the cause in the first place of your Damsel larvae's death). Surprsingly, and now I can say this with experience, larvae can often tolerate a fair amount of Ammonia (loses toxicity as pH drops) and if you keep the salinity high, Nitrite isn't much of an issue if it shows up either...

Matt