How often should I change water?

[Tenorplayer2008]

I have 10 Tetras, 5 of which are Neons, a bottom-cleaner (looks slightly like a tiger, don't ask me the name), and a catfish about 3 1/2 inches long, all happily in a 30- gallon tank. The guy who gave us the fish (he was an aquarist who had to move) said only about half every 2 months. Based on what I've read, that's way too long...

Also: How much do I change every time?

PS: Natural plants are populated in the tank w/ the fish...

[Harry Tolen]

A general rule of thumb would be 30% once a week or so. You should also clean the filter(s) every other week, rinsing the media out in the tank water you are removing so that you don't kill off the nitrifying bacteria with chlorine.

What kind of filtration are you using, by the way?

[spd7143]

Well crap, I'm glad I read this thread albeit too late. I rinsed my sponged in tap water first time around. Guess that would explain some problems I'm having.

[Gunnie]

Unless you are currently cycling your tank or you just added some bio spira, I don't think you can do too many water changes. I clean my tanks every week and change out about 40% of the water as I vacuum the gravel. Keep a check on your water parameters if you think your biological filter is gone. If your ammonia level registers on your chart, you may have destroyed all your bio bugs, and may have to do even more frequent water changes until the bacteria builds up again.

[JesseJ]

For a fully stocked tank a 50% change every 2 weeks is what I do. Your tank is understocked and has plants which will take care of a lot of wastes for you. I think that a 50% change once a month will probibly be fine unless you add more fish.

[kveeti]

Each tank is an individual, due to fish load, filtration, plantings, etc. If the tank is already established, you should at least get a nitrAte test kit. That will tell you how much water you need to change for your tank. If your readings are very high, you may have to do more water changes at first and then, eventually, you will find a comfortable percentage to change each week or two to keep your readings in the range you want. NitrAte is only toxic in high amounts. I like to keep mine at 10 ppm or lower. Some people pick “20” as their maximum. I believe you can go as high as “40” but lower is better.

[RTR]

Agree strongly w/kveeti's good and clear explanation.

[babypimpin]

any input on how often i should change my tank water?

I've got a 6.5" red snakehead in a 30 gallon tank
and thats it...
fake plants..no real plants...
right now im changing about 30% every 2-3 weeks...
i figure im extremely understocked...and one fish cant possibly pollute the water that much..especially when i feed him only 2 feeder goldfish ever 3 days...

[JesseJ]

That sounds fine to me but I think that kveeti gave the best method for figuring that out.

[Hound]

Hey Tenor, my mom lives in Arkansas and last time I visited her I'd swear she was 30 mins from everything in the state. That being said the best advise anyone can give is to get a nitrate test kit and figure out your water changes from there. One thing no one has mentioned is that you should use some sort of gravel siphon when you do change your water to remove excess waste that will build up and eventually really do some damage.

[Tenorplayer2008]

We just added 6 new fish( 4 Zebra Danios and 2 that accidently got in the net @ the petstore!) and 2 fiddler crabs that are always eating... something at the bottom...
any change in cleaning?