The Fry Tank [a Sub-faq For Newbies]

[Annastasia]

So, you have fry. Congratulations! You already know about two options for raising them, if you've read Neale's (Nmonks) post about Breeder traps/nets. If you haven't, you can read it here.

But there is a third option. A breeding tank! Breeding tanks can be anywhere from 5 gallons (19 liters) up. I always recommend at least a 10 gallon (38 liters), though. If you are planning on raising larger fish, like Swordtails or Mollies, I'd look at going for a 15+ gallon (57+ liters).


Setting One Up:

The Temperature is good anywhere from 75-78F (24-26C). I would definitely recommend a heater for fry tanks, even if you keep your house warm. A heater will prevent temperature fluctuations which can stress fry out very much.

For filters, you basically have two options.

1. A Sponge Filter
2. A Hang on Back (HOB) or other filter.

I personally recommend the sponge filters. There is then no chance of the fry getting sucked up, and they work very well giving you both biological and mechanical filtration. I use them in all of my fry tanks and love them! You can also make your own sponge filter very quickly and easily. Instructions can be found here. The only draw back to sponge filters is if you have a larger tank you need a bunch.

If you choose to go the HOB or other another filter route, make sure you get one that isn't going to be too strong. You don't want your fry getting blown all over the tank all the time. Also, to make sure they don't get sucked up into the filter, you can cover the intake with a Breeder Net or pantyhose. You will have to clean them off often though, as they tend to get gunked up.

Decorations can be anything you want. Plants are good, as are rocks, wood and general places for them to hide. Thick plants seem to be a favorite with mine. They can disappear into there, and fool their brothers and sisters as to where they are!

Now, on to substrate. Sand is a good choice, but some find it hard to clean. Gravel is okay, but you need to make sure you don't get very big or heavy gravel, because sometimes fry can get stuck in it and get crushed. Bare bottom is also fine, and some find it easier to clean.

Speaking of cleaning...how are you going to clean your fry tank? Fry need good water quality, and they are sensitive so lots of water changes! Don't worry about doing too many! You can do water changes using an airline tubing siphon you make, or a turkey baster so you don't suck up the little babies. Another option is to shine a flashlight near the tank. Most babies will go either towards it or away from it. Then you can clean where they aren't. This works well if you do a water change using a siphon or gallon jugs.


How to use them:

There are two options for using breeder tanks. You can either

1. Put the pregnant fish in there before she gives birth, then move her out after the fry are born, or;
2. Let the mother give birth in her normal tank, then move the fry over to the breeder tank.

If you want guaranteed safe fry, putting the mother in the tank before she gives birth is usually the best option. As long as you have some plants and decorations in there, most fry should survive. Move the mother out as soon as she is done giving birth, just to make sure she doesn't eat her fry. The best way to move her would be using a small container, so she doesn't have to be lifted out of the water during transfer.

If you are going to move the fry over to the breeding tank from the main tank, test the water parameters in the two tanks. If they are the same, you don't have to worry about acclimation too much. If the temperature is a bit different, just float them in a bag (You can use a Ziploc or any other sandwich bag) for about 10 minutes. If more then the temperature is different, do the normal full-blown acclimation. You know the drill....float for 10 minutes, add water, wait 10 minutes, add more water, wait 10 minutes etc. You can also do the drip acclimation method, if you want. More information on this method can be found on the bottom of this page.


Keeping The Tank Cycled:
Another thing commonly wondered is how to keep the fry tank cycled? The easiest way is to just stick the filter in one of your main tanks, and just let it run there until you need it. It will keep beneficial bacteria on it, and you don't have to keep the fry tank up and running all the time. Or, if you'd rather, you can take some medium from your main tank's filter, and put it in the breeding tank. If you have the same kind and size of filter, you can put it right in there, otherwise you can just stick it in the tank. You can use some gravel if you are in a real pinch, but you need to very careful and watch the water stats closely. There is still a lot of debate as to how much beneficial bacteria gravel REALLY holds, so just be careful.



I hope this has answered some of your questions on breeding tanks! Questions and Comments are welcome.

 

[nmonks]

Good stuff.

Couple of comments though...

If you're going to move a pregnant female, I'd recommend using a yoghurt pot or similar rather than a net. I reckon lifting a fish out while it is still in a water puts less stress on its body, and that must reduce the chance of miscarriages. In fact, I tend to use yoghurt pots for moving baby fish and anything spiny (like Corydoras) as well. The 500 ml size pots are especially useful.

As for keeping the filter media healthy while the breeding tank isn't in use, that's good advice. The other way to solve the problem is to remove some medium from your main aquarium's filter as and when required. At a pinch, even the gravel from the main aquarium can be used. I use a bubble-up box filter with my halfbeaks, half filled with gravel and topped off with filter wool.

Cheers,

Neale

 

[corpse fish]

This is totally awesome, it answered every single question i had, since i was getting worried about how to move/house my baby fry. one qusetion though, you said they didnt need a light, so would they do ok without the hood?

 

[Annastasia]

Thanks guys.

Neale - I added in your points. Thanks. The only one I skipped was the gravel part, because it's been found out it really harbors very little bacteria. I personally wouldn't risk fry in a tank that may not be cycled. Even though the load will be small (Well, depending on the batch), I like being safe rather then sorry. It is an okay solution if you really have no other choice, but hopefully people will be reading this before they set-up their tank.

Corpse-fish - I didn't say they didn't need a light, did I? I just didn't cover it because really any kind of light is fine. I'd just stay away from extremely bright ones that may stress them out. They can do without a light though. I would have a hood though, just so you can be sure there are no jumpers and also so other things (Your cat, for instance) can't get into it. It's just safer. Glad it answered your questions though.

 

[nmonks]

Hello Annastasia,

Re: gravel. I think it depends on the type / size of the grains. I use fairly fine (2-4 mm grain size) gravel, and it works very well. But the rounded, rather pebbly stuff may well not be so good. I'm sure the coated gravels (coloured gravels especially) are the worst. Mixed with some filter wool, I'd be pretty confident that gravel of any time should innoculate the clean filter wool and set up some biological filtration rapidly. Perhaps not ideal, but at a pinch, adequate.

Obviously, you use what's to hand, and keep track of things with a nitrite test kit. My experience is with halfbeaks, and both adults and fry seem to be somewhat indifferent to high levels of nitrite or ammonium, so perfect filtration perhaps isn't as important here as with, say, fancy guppies.

I'm not sure whether lighting is essential per se, but I'd guess with things like platies and mollies you want at least some algae growing in the tank. Daylight will be fine for that, but I'd always limit direct sunlight to only a 3 or 4 hours a day so as not to overheat the aquarium.

Cheers,

Neale

 

[Annastasia]

Fine, fine, I'll add in a little note about it since you are so insistent.

I'm still going to add a warning about it though. We'll compromise.

 

[nmonks]

No, no, I think it's right and proper you err on the side of caution. I was just saying that I get away with gravel in filters. But I (think I) know what I'm doing, and can (usually) spot the signs when something is going wrong. For newbies, I definitely agree with you about recommending the best types of filter media.

Cheers,

Neale

Fine, fine, I'll add in a little note about it since you are so insistent.

 

[Weaver]

Many thanks for the article Annastasia
Youve answered two questions I had but was afraid to ask after my mini rant about fry posts last weekend