What would cause aquarium water to turn hot pink over night, with a little bit of scuzzy scum? The water in my hospital tank was clear thursday morning and then hot pink by thursday night/friday morning.

Nothing was added, changed, removed. No medicine in there to turn it pink. The scum stuff also smelled kinda fishy.

Never heard of this. Do you have kids that may have done something to the tank? Where does your water come from? What are the water parameters?
Red tide? lol sorry i had too.

That doesn't seem natural. I suspect tampering.

Agreed, Never heard of anything that can turn water "Hot Pink".

No kids, its in the back room of the house and no one goes in. In fact, no one is home all day long. I live in Los Angeles so the water here is Very treated, I get it from the tap which runs through the house purifier and then dechlore it. I wish I had taken a picture of it but I was too worried about getting it out. It looked like someone had literally poured red dye into the tank. It was clear, not opaque, and there were some fine bubbles on the surface and red scum along the edges at the waterline.

Its a 10 gallon sick tank with two blue gouramis that I'm treating for acute bacterial infection. They're both doing wonderfully, lesions healed and hearty appetite so hopefully this wont be a setback.

Ammonia: 0
Nitrate: 10
Nitrite: 0
PH: ~7

Its a bare-bottomed 10 gallon tank with a HOB filter rated for 40 gallons. It has a filter bag filled with ammonia pure and no carbon (for the meds). It has a small heater, and an air stone. It also has a handful of floating water spite? (some leafy bright green plant, lacy fronds with long roots that hang down) to help with keeping the water clear.

The only thing I can think of thats red is their food, but they always eat everything and there was no food build up.

someone dumped a chemical or dissolving item in the tank that turned the water pink, and that chemical may have killed enough microorganisms in the water, filter and substrate to create that scummy surface slick. a fish tank in a public space should always have the top enclosed by a canopy to protect both the tanks contents and curious fingers from hot lighting.

This is the only thing I could find...http://en.allexperts.com/q/Freshwate...sh-water-1.htm

Many fish medications depend on semi stable chemicals, that react and or breakdown, in normal aquarium conditions. It wouldn't be surprising if light or chemicals in tap water (maybe even pH of the water) broke down the meds with time.

Let me ask you did you conduct a series of water changes after the last time you treated it with medicine?

The only thing I can think of is potassium permangenate (sp?).

What are you using as meds for the infection? In that link I posted they said "I've been treating him with tetracycline." Would that have anything to do with the color?

The tank didn't have any new medications in it. It has been treated with anitbac bath (a 3-4 weeks ago, turns the water green yellow and is deactivated by light), maracyn two (a bit over 2 weeks ago), maracyn tc (a week ago-this is tetracycline but hasn't been added in a week. It sometimes makes the water cloudy but I don't think it would turn the water pink. I read the link you posted and they were probably dosing with tetracycline drops which are pinky/orange. Or the fake flowers? This one seems interesting but they don't conclude anything) and they get antibiotic food.

The tank is in a private back bedroom in a private home. My mom and 17 year old sister are the only inhabitants, neither of which would have touched the tanks in any way and help me with water changes when I'm there. So deff no tampering of any kind. It was my mom and sister who called me freaking out in the middle of my MCAT class to tell me the water was pink.

Is there anything that could naturally turn the water hot pink? or a funny combo of meds? The tank has been med free for a while, with the exception of some copper sulfate that i put in about 3 weeks ago (its active for a month) and some epsom salt. This is so puzzling! The water was changed twice in the past week. Maybe a connection to the link? But that really sounds like dye from fake flowers...and I don't think the expensive antibiotic food that won the breeders award would leech dye in the few seconds before they eat it.

Argh! I ended up doing a 100% water change, or as close to it as you can get running one hose draining and another one adding.

I have to go for the red algae. It is something that gets into the water at the water treatment plants. I dont know the full name of it but I did some summer work at a treatment plant and that happened. There answer to it was just to up the chemicals in the system. I will try to find out more about it and also try to contact some of the guys that I worked with and see if they have more of a answer than that.

Thank you! That would be awesome. I've never heard of red algae in freshwater before.

I did some googling.. you're not the only person with pink slime.. and she had sick fish too..

http://www.fishdoc.net/faq/faq_details.php?faqId=120

interesting.

I do know red algae blooms in the bays are really bad for fish. I think mostly the algae sucks up the oxygen from the water and thus the fish die in hundreds becuase they suffocate. But also some species of algae blooms are also toxic. So we aren't allowed to eat fish we catch during a red algae bloom in the Texas bays. And we can't harvest the fish kills to make into fertilizer or anything useful. But that is in brakish and salt water.
I have heard of red algae blooms in lakes.. but they were really high salinity lakes like the ones in Oklahoma and Texas along the red river. I've not heard of it in a fish tank before.

Are you very sure that no one tried to doctor your fish
with potassium permangenate? it would stain everything esp
slime a pretty hot pink color. You can nuetralize pp easily with
hydrogen peroxide... potassium permangenate is a much safer
ich/fungus remedy than copper sulfate... that is why I ask
even though it's been asked.. if your sis or mom might have
tried to help.

hey.. this is a freshwater tank we're talking about right? not brakish or salt?
If it were a salt tank... could be coraline algae.