Water change killed my fish! Help!

[rose1968]

This is my first post to this group. I am so upset I just don't know what happened!!

I have a 45 gallon saltwater aquarium. I am relatively new with saltwater (the tank has been going for about 6 months). I have had great success. I had the "basic" fish--3 damsels, a cardinal, a mandarin, sandsifting starfish, mandarin, scooter blenny, clam, serpent star, a tomato clown, sleeper goby, goatfish, and one or two others. I had a death or two (two anemones a few week back) but otherwise everyone was happy. Then I just noticed that my serpent star's legs were literally breaking off! I didn't know what to do, so I decided to do a partial water change.

I retrofitted my hood as recommended by the aquatics store about 2 weeks ago. At that time I also purchased saltwater from them. I did a water change about 5 hours ago, just changing out 5 gallons of water. Well, all of my fish are dying! In just those few hours I have lost my mandarin, cardinal, goatfish, I think the serpent star, and the rest are barely alive.

What happened?? I added all of the chemicals that I normally do except for a new buffer that the aquatics store sold me. I do remember the store telling me they use a different type of saltwater than the other store that I had been going to. Is it that the saltwater cannot sit for 2 weeks?

Please, any help is most appreciated!!

[aquaman67]

The first thing that stands out to me is IMO you have way too many fish in a 45 gallon tank. I counted 9 "plus one or two others."

Saltwater is much different than fresh. You can't stock it so high.

You didn't mention any water parameters.

When you do a water change you need to match temperature, pH and salinity. You didn't mention if you checked these before doing the water change. DId you check any of those before you added the new water? And how fast did you add it?

Even if those things don't match, you can add the water very slowly and shouldn't have a problem.

You said you are adding chemicals. What chemicals and what are you testing for? You should never add anything you don't test for and the test says it's low. Saltwater can be used within hours of being mixed. Mixing overnight is the most I've waited. Two weeks isn't necessary.

What type of filtration are you using? Do you have live rock?

I'm sorry to hear about your losses. Let things settle down. I hate to say it, but water changes would help. Maybe look into mixing your own so you'll know where the levels are.

[rose1968]

Thanks for your reply. I know it sounds like a lot of fish, but they were all small--about an inch or so.

The water was the same pH, temp, and salinity. The only chemicals I put in were "maintainace": buffer, Novaqua and Amquel (all which say are safe for saltwater).

I have live rock. I have a skimmer and my filter is an Eheim Canister Classic 2213, up to 66 gallons.

Thanks so much for your help.

[aquaman67]

Why are you adding buffer, Novaqua and Amquel?

The buffer may have boosted your alkalinity amd pH too high.

Without knowing what your pH and Alkalinity levels are, it's hard to help.

I'd stop adding anything until you get this figured out.

Can your fish store test your water if you don't have your own kits?

[rose1968]

I just brought the water to a store. The pH was low (7.8) but everything else was fine. I added the buffer, AmQuel and Novaqua as part of maintainance. I was told to do this every time I did a water change.

Trust me--I am not doing anything else until I get this nightmare under control. I also just bought a powerhead, as the store said might help, to see if that will save the 2 fish who are left.

[becky_e]

I have a 45 gallon tank, too. It's been up since April and I have a grand total of 5 fish in it! 2 pajama cardinals, 2 neon gobies, and 1 yellow watchman goby. I still want a couple more fish, but I'll be stopping then. Your tomato clown can get up to 5 inches long. It's one of the bigger clownfish. The goatfish can get VERY big. They are cute when small, but can get to be 1 foot 8 inches according to liveaquaria, and that seems a bit small. The damsels and the tomato clown will fight a lot. The tomato is also one of the more aggressive clowns and damsels and clowns are in the same family so won't tolerate eachother.

First you need to get a test kit and check your water parameters. Test for ammonia, nitrites, nitrates and pH. It sounds like you've got a reef tank (clam and anemones.) You may also want to test your calcium. My tank is a reef and we had a bit of a pH/calcium problem that has now been taken care of. We use Seachem's products and they are fixing the problem with the pH and calcium. You don't want to start using these products without the test kits.

You also may want to reduce your fish load a bit. Removing the damsels would probably be best. I have 1 damsel in a 10 gal. tank with nothing but a hermit crab and 2 snails and it seems content. Don't replace the goatfish or the mandarin. You can do some searching on this forum about mandarins and can see why you probably shouldn't get another. Also, mandarins and scooter blennies share similar niches and probably were starving eachother out.

Good luck, I hope you can get your tank stable.

[tanker]

I just brought the water to a store. The pH was low (7.8) but everything else was fine. I added the buffer, AmQuel and Novaqua as part of maintainance. I was told to do this every time I did a water change.

You did not post any parameters. If you had ammonia (may not be surprised with that much fish) it may not be toxic at a low PH. But when you did water change and added buffers, which brought PH up, ammonia became toxic.

[Adonis Mt]

I have 3 fish in my 75 :o (a yellow tang, a fijian damsel, and a dottyback)

[wayne]

OK, I know they were small but you still had too many - they do grow. Also the scooter and mandarins were bad choices for feeding, and goatfishes get huge.
Changing the hood wouldn't have done anything. I need to look and think here...

You changed 5 gallns of water that's been sitting for 2 weeks. Seawater can sit that long but it would be best to aerate it first. You also added amquel (good, but not necassarry if you're buying water form a store), and buffer. You've been adding buffer regularly, but you still have a ph down to 7.8??

I'm thinking your pH has been going low, and that might be a result of all the fish in your tank producing waste - this drives pH down. This stresses the fish. How much skimmate are you getting, how much live rock do you have? Ammonia and nitrate tests would be interesting here. Anyway you added some water that was a bit high in pH, bit low in temp or O2 or something was different. Anyway this put strss so high you lost one fish, get an ammonia spike and as you have a low pH anyway (god knows what it is between buffering?) bang, bang, bang down go the others. Or the higher pH ammonia more toxic theory may well be happening as well.

If I was you I'd wait to see what happens. Buy water from your old store. Get some test kits too for pH, kH, ammonia and nitrate if you don't have them. Then buy a bag of salt, a bucket and a cheap powerhead and learn to make your own water.
And good luck