i recently cleaned my tank until there was about foot of water left and moved the tank across the room. I filled it up and everything seemed fine for about 2 weeks then the water turned red. then it turned purple, so i decided to do something. i drained about 1/4 of the tank the filled it back up with clean water and put a power filter in and the water is still red! does anyone know what this is? any suggestions would be greatly appreciated.

i forgot to mention that i have also removed everything from the tank except the gravel and my fish. i have 2 goldfish a rope fish a royal pleco 4 buliva sharks or whatever their called and 2 flaming tetras.

How big is the tank? I assume your tap water doesn't have any colors in it? If the only things in the water are gravel, the tank itself, and the water itself then the colors would have to come from them. The fish won't make the tank water go red or purple. How intense were those colors? Those aren't normal colors for aquarium water to turn into at all. Red water can be due to high levels of iron, rust, leaching gravel, and so on. Was the gravel used before? Did you disinfect it when you redid the tank?

To disinfect the gravel, put it into buckets with dilute bleach. Wear rubber dish washing gloves and stir the gravel around. Let it sit in there for a day, stirring occasionally. Then, change the water for fresh water with dechlorinator and repeat the above. Then, the gravel should be sterile, at least from organic entities but not necessarily inorganic ones like copper or iron.

Do a water change and run some fresh carbon in your filter. That should remove most discoloration. You may have to replace the carbon.

Rarely, there may be some algae that grow that are reddish but it would be pretty rare for those to be suspended like the red marine algae that compose red tides. Those are cyanobacteria and highly toxic. If you had that in your tank, the fish would most likely already be dead.

Good luck!

my tank is 40 gallons and my tap water doesn't have any colors. the good thing is i have replaced the carbon and i think i have located the problem. one of my bala sharks had fin rot so i put medicine in the tank and the medicine caused major foaming at the top of the tank. then the water started to change color. would the medicine change the water color red?

Oh! You didn't mention having used medication. I assumed you hadn't. Many medications contain dyes. Some "medications" like malachite green are themselves dyes. I can't think of any medications that are red offhand but it wouldn't surprise me. The medications can themselves be colored or contain pH indicators that change color with the water's pH.

my water is now fine thanks to your advice. but now i have another problem. my big 6" red capped oranda has a weird red spot on either side of his top fin and its starting to swell out. what should i do? i will try to post a picture as soon as i can. please help.

i got some pics but there not very good. hopefully someone can identify his problem and tell me how to fix it. how do you get such good pics Robyn?i dont know how to put the pics on the page. could you please help.

Most of the photos I take are horrible! People send me a lot of photos. In order to post a photo here, you must have the photo on a web site somewhere. Then, when writing a message, click on "IMG" on top of the text box to put in the URL (web site address) for the photo. If you don't have a web site, there are tons of free sites for photos. I also sometimes put them on my page.

Red lumps could be any number of things so a photo would be helpful. They could be physical injuries, parasites (usually anchor worm or fish lice injured areas), fish tuberculosis boils, tumors, cysts (fluid filled), and so on.

The spot is on both sides of the dorsal fin?

ya the spot is on both sides of his dorsal fin but its more like a spot on 1 side and a line on the other. i think these pics should work if not then i have no idea. oh i just had a good idea il just email the pics to you and then you can tell what it is.