Advice on community tanks

[EllaFish]

I am planning to set up a community tank, but since I know nothing about community tanks I would love any advice and comments people could give me. Here is my planned setup:

5 Female bettas
5 Mollies (probably female)
5 Guppies (probably male)

20-30 gallon tank
Filter for the tank size (or less, for the Bettas?)
Thermostatic heater for the tank size
Gravel, decorations, silk plants, live plants

Maintenence equipment:
Scrubber
Siphon tube/gravel vaccum
Will probably have tank cycled first
Holding tank for during cleanings

Main questions:
Best tank size?
What speed should the filter be?
What kind of filter/filter media should I use?
Should I have an airstone?
How often should I do cleanings/partial water changes?
What should I use to control algae?

Thanks in advance for your input!

[thekoimaiden]

With that amount of fish, you are going to want the 30 gallon tank. Your filter should be rated for at least 30 gallons. The Aquaclear brand is my favorite HOB. They work hard for a long time, and they have customizable filter media. I don't use the carbon as it is very expensive in the long run and doesn't really do much for your tank. I just have the sponges and the bio-media in mine. I like the Aqueon Pro heaters, but the Fluvals are also great. A 30 gal is a good size tank to try live plants for the first time, but that decisions is ultimately up to you.

What exactly is a holding tank, and why do you think you need it? You never do a 100% water change on a cycled tank so you never need to remove the fish.

An airstone isn't necessary at all. In a cycled tank, you should do at least one water change per week. The volume is determined by your stocking level and just how many live plants you end up with. The best way to control algae is live plants and a timer on your light.

One last note, I would like to make about your stocking plan, livebearers will hybridize. The male guppies will harass the female mollies. Either get all male or all females. Females will probably fare better because they don't have the vibrant colors of the males; bettas will often attack male livebearers as a result of this. Livebearers will also do best in hard water, so if your water is very soft, then they probably won't do well.

[EllaFish]

Okay then, all females it is. What kind of hardness range would you recommend so that all the fish are happy? Or is there no such number, and I should change my stocking plan?
I guess the holding tank isn't really necessary, but I have all kinds of small tanks anyway and if I was doing something that would disturb the fish a lot I might move them out.

[thekoimaiden]

Unless you are completely emptying the tank (for example, to change substrate), there is no need to ever remove all of the fish. This is extremely stressful for them, but it is good to have a few extra tanks around just in case a worst case scenario happens (crack in the tank, natural disaster, ect).

It's better to stock the fish to your water rather than change the water for your fish. Do you know how hard your water is? If not, you should be able to find a local water quality report online. That should have the information we need, specifically the pH, GH (general hardness), and KH (sometimes called carbonate hardness).

There are levels of hardness at which all three of those fish can thrive.

[Kitty Whiskers]

Also you can run a smaller tank to use as a hospital tank for sick fish or for a quarantine tank for new fish.

[DoberMom]

I have a 30 gallon sorority with a pair of fancy guppies specifically because they constantly have babies witch is free food for my girls. I've never had a problem with the girls attacking the male guppy.

[kfryman]

Mollies are brackish water fish, meaning they require salt to be very healthy. "Freshwater for them is like bettas in an heated tank" forgot who said that... But yes trade the mollies for plagues or swordtails, as they are freshwater fish and they won't grow big like mollies do.

What are your water parameters? Those fish do much better in hard water, so if you have soft you will be looking at different fish.

[thekoimaiden]

Originally Posted by kfryman

But yes trade the mollies for plagues or swordtails, as they are freshwater fish and they won't grow big like mollies do.

Not laughing at you, man. Just the crazy things that spellcheck comes up with. I think he means platies.

[kfish]

Originally Posted by thekoimaiden

Not laughing at you, man. Just the crazy things that spellcheck comes up with. I think he means platies.

Lol! I was like... plagues sound like interesting fish. ;)

[EllaFish]

I would add enough aquarium salt for the Mollies, but not too much for the Bettas. I think I could find a balance.
No, I'll keep my fish free of plagues, thank you very much! haha.
Dobermom, I think she meant male guppies attacking female mollies, but if they behave for you,that's good.