Lionfish17

my boyfriend did a 75% water change this morning, and now our little guys all are suffocating... what can we do?

David C

Do you have an airstone setup? They work wonders on increasing the oxygen in the water.

Lionfish17

He's going to go get one :P

David C

Ok, they work really well, I use the whisper series of airpumps because they're really quiet, but I used to have the cheap one from walmart and it worked fine.

sirdarksol

A couple of questions:
Which tank is this?
What are the ammonia, nitrite, and nitrate readings in the tank? It's very uncommon for a filtered tank to lack appropriate oxygen levels. Gasping at the surface usually is a sign of something else.
When he did the water change, did he treat the water with dechlorinator?
If it's a lack of oxygen, you can take a cup, dip it in the tank, and pour it back into the tank from about a foot up. The stirred water will help the gas-exchange.

If this is the brackish tank, the salt may actually be the problem. Only the "shark" in that tank is actually a brackish animal.

Barbrella

Doing a 75% wc can destroy the cycle, causing a rise in ammonia and nitrites.

Both of those contaminants can certainly cause the gasping you're seeing.

If you don't have a test kit, you really need to get one.

0morrokh

Hmm...for the most part I disagree with that. Changing any amount of water shouldn't have any affect on the cycle. However, if the tank was cleaned too well or the filter media was replaced along with the water change, that could kill the cycle. High levels of ammonia or nitrite could cause gasping, though I'm not sure if they'd build up in just a day, even if the cycle was damaged...

Doing a water change should add oxygen, if anything, so I don't think that's the problem.

I could be shock of some type. When was the last water change? Was the water you added the same as the tank water in all its parameters? Have any chemicals been used near the tank or bucket used for the water change?

I guess I should ask just to be sure...when you said your fish are suffocating, you mean they're gasping at the surface, right? Do you notice any other symptoms, like red gills?

Shawnie

there is very little if any beneficial bacteria in water...its more in the filter and deco, as well as gravel...

could be the temp of the new water was different than the tank. or maybe the water wasnt treated with some kind of conditioner?

testing the water parimeters would give you some better ideas on if it was ammonia or nitrites...

Barbrella

Yes, I assumed that anyone changing nearly all the water might overclean or change the filter floss and/or vac all the gravel at the same time, because years ago I did that very thing!

Shouldn't assume, I guess!

Lionfish17

We're pretty sure that it was just oxygen, because there all happy now. We do have a testing kit and all of our levels are fine.

Shawnie

I do 50-75% water changes every other day in my 75 gallon because im way overstocked...so that only helps the fish not hurt them

way more oxygen in new water for sure...and the bubble wands or stones do miracles ..glad your fishies are better!

COBettaCouple

The tanks are overstocked too and is something to take care of as soon as you could.