I am planning on getting a 20 gal tank to use as a growout tank for both my goldfish fry and my mollie/platty fry. Depending on funds/ space I might go for a larger tank, but it must be a rectangular footprint.

I am currently thinking of dividing the tank into three parts. The largest section would be about half of the tank and would have both the filter and heater in that area. The other half would be divided into two equal sections. So I have 1/2, 1/4, and 1/4 tank spaces avaliable for different sized fry. Depending on the size of the fry I might cover the last divider with pantyhose to keep the smallest ones from getting through it.

The smallest/ just hatched fry would go into the area furthest from the filter. The largest would be in the big section with the filter intake in it. The Idea is to graduate the fry from section to section untill they are big enough to either go into the tank with their parents (tropicals) if I want to keep them, or go to new homes.

I am thinking I want the two smaller sections to be bare bottomed. I am playing with the idea of adding a substrate to the largest section. Both to get the fry used to having it and to support plants in the tank. I would like to have a plant that forms short groundcover for the fry to play and rest amongst. I might put some taller bunched plants in a baby food jar in the smaller sections to give the fry somewhere to rest as well.

I would keep the tank heater set to 75 degrees so it is warm enough for the tropical fry but not too warm for the goldies.

Looking for suggestions on the following:
What type of plant would you suggest for groundcover?
What size filter (gph) for a fry tank containing both goldies and tropicals?
Would you go smaller filters and put two on the tank?
Where would you place the airstone? (which section)
What do you think about the half barebottom idea?
Is there anything you would change about my current plans?
Anything else you think I forgot?

I want the tank to look pretty as well as be functional because it will be in the livingroom and all the house guests will see it when they come in the front door. The goldfish fry would be the longest term occupants as the tropical fry should be big enough to not get eaten within about a month of being born.

This is an interesting idea..... It has some merits.... any you may be able to get it to work for you.

There are a few things that you may wish to consider, though.

Goldfish fry grow ideally at 69-71F, depending on breed. They do not do well at 75F. You will experience premature hatching and/or death at 75F - at least from spawning to 1 week or so.

Goldfish fry should be kept in shallow water for the first few days, at least. They need to be able to make a dash for the surface for that first, all important, gulp of air to fill their air bladders. If the water is too deep, you will get sinkers and floaters as they grow.

Goldfish fry will only grow quickly and well if given adequate water volume. About 25 fry (1/2 inch in total length) can be kept in 10 gallons (6 in your 2.5 gallons proposal), but when they reach 1 inch in length, this can only be about 7-8 (2 in the smaller volume). My fry typically reach this stage at about 3-4 weeks.

Goldfish fry need to be fed a careful diet of special foods to enhance the various characterisitics of their individual breeds. Tropicals do not necessarily have these restraints. It may be difficult to feed different sections the foods needed. It is a fine divider, indeed, that can screen out baby brine shrimp!

Goldfish fry should be fed at least every 4 hours or so. This makes for very dirty water. The water needs to be cleaned carefully and often - kept in pristine conditions.

"Moving" fry between sections is often impractical. Scooping a fry into a net can cause body flaws - damage tails and backs in a tiny fish. Scooping them into a cup is not easy - and can cause problems if not done carefully.

A filter that is carefully sectioned off can, indeed, be a boon in a fry tank. Water quality is really what it is all about! My fry graduate from an air driven sponge filter to a power driven sponge filter at about 2-3 weeks. The power head is then soon replaced with a full filter, with the intake covered completely with a sponge. As the fry grow, the sponge can be removed and the intakes covered with a combination of needlepoint plastic and netting. The plastic holds the netting away from the intake grate - making the suction much less on the fry.

Your idea has merits - and will work with 10 fry or less. Careful feeding and cleaning will also be necessary - but they are also possible. I use plastic plants with small, soft leaves in my fry tanks. These have stones glued to the bases with aquarium sealant to keep them on the bottom. The fry love to use the plants to hide in and sleep in. The plants also will grow an amazing crop of fuzzy green algae - a constant food source for growing babies. I expect any real plant with small, soft leaves would be fine. Elodea is a good one for food.

I start with a sponge filter run on air. I then use a power head pumping approx. 160gph per 20 gallons of volume, plumbed through the sponge filter. As the fish get larger - about 1 inch in body or less - they are fine with the full filter strength of a normal 10-15 times turnover in the water. Fry with more delicate tails (Broadtails, Phoenix, etc) will have the intakes covered with plastic and netting. Ranchu/Lionhead/Shubukins do fine with the regular grate. They are strong and hearty baby fish. Baby fish need pristine water to grow well. This means good filtration and a regular cleaning regiment. If you are stocking heavily (more fry than described above) you will need to tend the water at least every day. I usually place a bubble bar in all my fry tanks. I buy the ones that make a very fine fizz of bubbles, and turn them very low. As the fry grow, the bubbles are turned up. This can ensure that there are no pockets of stagnant water.

I think that with a setup as you have described, you will have quite a conversation piece in your room! There are not many who can show the many stages of baby fish in one place such as you have described! I think it sounds like an eye-catching setup.

Thanks for the input.

The total tank size would be at least 20 us gallons. For new goldfish fry I have breeders nets and could hatch out the eggs in the parents coldwater tank, let them grow a week or two before transferring. But I do not think that I will be able to hatch out any more eggs this year. I am at my limit of nets and such. All of my goldie fry would be at least two weeks old before being transferred.

The tropicals seem to do much better with being moved than goldfish fry do. Either way I have a carefully adapted plastic cup end I use to catch the little ones when I need to.

I will try what you suggest about the filter intake. I was just going to cover it with netting of some sort. But keeping the net from directly touching the intake area makes a lot of sense.

I know that this tank will need a lot of attention. But at least it is one tank needing it and not both of my larger tanks. Part of why I want to set this up is to reduce the maintenance times for the other two tanks the fry are currently in. Also to not have to move the goldfish fry once a week would be nice. I also think it will be an upgrade to have a tank to themselves and not just a tiny breeders net. The goldfish will go in first and I will see about adding the tropical fry after I see how things are going.

Good news! I was looking on craigslist and saw an ad for a petstore that closed. All the inventory is %50 off or more. So I am getting a new 29 gallon tank kit this weekend for the fry.

The filter that comes with the kit is a wisper 30. The lady selling the stuff told me it pumps 145 gph. Is this ok to start with? I can add another filter or upgrade in a month or two when the fry get bigger.

The fry I have left for the tank are: 1 fry just over 2 months old that is about 1 inch long without tail. 2 fry just over a month old both about an inch long with tail. 2 fry almost a month old both about the same size as the ones just over a month old. And about 18 fry that are 2 1/2 weeks old. That is a total of 23 fry.

If only the biggest fry were in the part with the filter intake, would you still have sponge over it or go to the needlepoint plastic and netting? If some of the smaller ones were also in that partition, same question. I will most likely modify the water return into the tank so it is redirected towards the back tank wall and not into the middle of the tank where the fry will be swimming.

I may at this point only divide the tank in half since the only big difference in size is between the oldest fry and everyone else.

I will probably start bare bottomed and possibly later add gravel on the one side to grow some plants. That will come after I get some more money.

I have decided for now to leave the tropical fry in the community tank. I might move those to my ten gallon tank if I can get some plants to take root in there.

Edit: Now all I have to do is figure out what to put the tank on.

Congrats on the tank you found.

I just have one thing to add. When I divide tanks for fry I find the tank divider itself is a real pain to keep clean. For some reason whatever I use- and i have used proper aquarium perspex tank dividers and also home made netting -gunk collects from uneaten food
or just general muck on the dividers really fast. This is so hard to clean because of the difficulties with putting your hand in and around the tank at angles with delicate fry at every turn.

If you only have one division it would be much easier to clean than more. If it were possible a tank on the floor or low down might be best so you have elbow room and maximum light to see what needs doing and whats going on.

I'd make sure the filter return splashes into a corner not centrally definitely.