Fry tank questions

[sueandherzoo]

I just wrote a long and detailed set of questions but don't see it on the boards - perhaps I only THOUGHT I hit "submit"? In any event, if it shows up later and this is a duplicate, please accept my apologies.
I hope to soon have a brood of Southern Erectus fry and am reading all I can to find ways to be as successful as possible, but I have some questions.
There is a method (Kriesel?) in which you place a plastic fish bowl (with openings cut out and covered with mesh) inside of a fish tank. I think I like the concept because having the fry in a more concentrated area makes feeding easier and cleaning the tank less risky, but if we have openings to allow the waste products to flow out and clean water to flow in, what's to keep the food source in the fish bowl? I almost think you need a way to close the openings during feeding and then re-open them after wards but not sure how I'd do that.
When we do the siphonings and cleanings, do we siphon outside the fish bowl, inside, or both? If both, I'm not sure if there's much benefit in having the fishbowl. I assume we want the waste and dropping to flow outside the bowl where we can suck it up, right?
Green water: I'm guessing this is a method in which the fry are living in high concentrations of plankton/food products but how do you keep the ammonia at controllable levels in that environment? I like the idea from a nutritional standpoint but would the water be too foul for the fry to survive?
Last question (for now): I live close enough to an ocean - is there benefit in me taking a ride there every weekend to obtain water (or anything) that might benefit the fry? Might the water be full of microscopic food sources that I can't possibly replicate from the LFS? It would be well worth the trip if it would increase the survival rate.
Any info or thoughts are welcomed and appreciated.
Sue

 

[reefnutpa]

Hi Sue,
Back when raising fry successfully by average hobbyists like you and I, the accepted way to do this was with the "kreisel" nursery. I used it for over a year, with O.K. success. It's most useful when raising palegic fry (those that don't hitch) such as Kuda, Reidi, Northern Erectus, etc.
Basically to make one, you take a one or two gallon PLASTIC drum style goldfish bowl, cut a hole on both of the flat sides, then glue very fine mesh (I used a freshwater fish net breeder trap and cut it apart). You then poke a small hole 1/2 way down one of the curved sides and insert an airline tube about 1/4". The airline is connected to a valve, which in turn is connected to an air pump. Turn the valve just enough so a SLOW STEADY stream of bubbles comes out of the airline. Not enough to blow the fry out of the water This slow, steady stream will create a circular motion within the bowl and keep the fry suspended in the water column instead of floating to the top. The bowl with airline attached then gets hung inside a filled, sterile tank. You feed the fry inside the bowl, the fine netting prevents the bbs from escaping quickly. You can use a HOB filter on the actual tank to remove the bbs that does escape. There are pics and detailed instructions elsewhere if you seriously want to consider one. I think I still have some old ones I no longer use if 'ya want me to plop one in the mail for you to look at/try to use.
Personally, unless you have palegic fry... a standard tank with sponge filters will work just as well if not better. The majority, I believe, are not using kreisel nurseries any longer.
As far as using ocean water for fry..... NO Unless you are going to purify it, blast it with a UV sterilizer, etc. I would not risk it. You would be basically turning your captive bred fry into wild caught seahorses by introducing them to all the bacteria, pathogens and parasites found in untreated natural sea water. For a fish tank, reef, etc it is a do-able thing.... but not when dealing with fry. The tank really needs to be as sterile/clean as possible IMO.
Green Water is a way to use live algae cultures to help control ammonia in the fry tank AND gives an added benefit of being a food source for the bbs, rotifers, etc that you would be feeding fry. This method is still used by a few people, I believe, but not many.
Wow, I certainly know how to ramble on and on. Any other questions, just fire away!
Tom

 

[sueandherzoo]

Hi Tom.
You may consider it "rambling" but I soak it all up and am always disappointed when I realize I'm nearing the end of your posts. Thanks for the down-to-earth, easy to understand, and honest information. It's exactly what I was looking for because a lot of the stuff I've been reading is quite old so I don't know if these methods I read about are STILL the suggested way or if that was then and this is now.
OK, so I guess the primary benefit of the Kriesel method was to keep the water flow circulating properly for the non-hitchers. Since Southern Erectus hitch right away that's not an issue. I thought perhaps there would be benefit in having the fry in a more congregated area for ease of finding food but if the BBS get through the mesh anyway, there's no point in me bothering with the inside fish bowl.
I'm probably not savvy enough or educated enough to experiment with green water at this newbie stage of the game so I should stick with the basic and simple approach.... I'll keep the sponge filter going in the 10 gallonand do twice-daily siphonings once I have fry in there.
I did just think of another question: why does everyone suggest rinsing the newly hatched BBS? What are we rinsing off of them? They were hatched in saltwater and are being placed in saltwater so why the rinse?
Thanks again.
Sue

 

[reefnutpa]

The reason for the rinse is to get any debris, detritus, and other crud (love my scientific terminology, huh?) off of the bbs. Another reason, and probably the most important is because the bbs hatching water is filthy after the bbs hatch. Try testing some of it or looking at it under a microscope after a big hatch - nasty stuff!
So, you rinse the bbs to rinse off the nasty hatching water and to clean them of any stuff that may be stuck to them that you don't want to introduce into the fry tank.
Tom

 

[sueandherzoo]

OK, making mental note to always rinse BBS before moving to fry tank. But HOW????? What do you use to contain them while you're rinsing them? They are so small they are going to rinse through a net! If I suck them out of the bottom of the breeder with a turkey baster then where do I put them to rinse them?
Next fry tank question: it's important to "cycle" a fry tank to help with the conversion of ammonia into nitrites and then nitrates but where is the beneficial bacteria going to grow? There's no live rock or live sand or macroalgae, the only place for the good bacteria to go forth and multiply is in the filter sponge, right? Do I want to use a HOB to add to the filtration? It just doesn't seem like a bare bottom tank with a sponge filter is going to have enough surface area to hold enough good bacteria. Should I at least seed the fry tank with some bottled bacteria?
Sue

 

[teresaq]

sue you can buy a brineshrimp net. its almost like cloth.
my understanding is just the tank, sponge filter. see if you can find the article on cycling with pure ammonia.
T

 

[reefnutpa]

Hi Sue,
You will have MUCH greater success if you cycle a fry tank. You are correct, the bacteria will only grow on the sponge filter. That is why I use two of the 2nd biggest Hydro sponge filters - to get plenty of bacteria growing and keep the tank as stable as I can.
Honestly, while I had a tiny bit of success using non-cycled fry tanks, things got much better once I took another's advise and added the sponge filters. Best thing I ever did.
I use both brine shrimp nets and rotifer sieves to rinse bbs. I do not recommend a HOB filter in the nursery. You will be siphoning the bottom of the fry tank at least two times a day to remove debris (at least you should be). The risk is too great that the tiny fry would either get sucked against the intake or that the flow would be too much for them and they would exert too much energy trying to swim/catch their food in the current.
Tom

 

[sueandherzoo]

K, no HOB, adding another sponge filter. I have some "Biozyme" -- should I put some in to start the beneficial bacteria growth?
What factors determine whether or not a male seahorse is going to produce. Even though he gave me that batch a month or so ago, he doesn't look at all pregnant right now. Of course I didn't think he was ready to produce the last time he surprised me, either, so I guess I'm not the best judge of fertility.
Sue