Why My fish Die?

What type of fish are dying, how do they look before they die, and how long did you have them? What is your quarantine process?

 

How long do you acclimate the fish before putting it in the tank? How many fish do add in at one time?

Chris

 

You do realize that most hawkfish are preditorial fish and will kill and eat other fish, might be the answer to your mystery. Jeremy(waverz) had this same mystery of fish disappearing and after he got rid of the hawkfish fish stopped dying. Hope this helps, Jason

 

The long nose hawk has a smaller mouth than most hawkfishes. I don't see how it could be eating any of his fish, much less surgeonfish. I might be worried about the shrimp though!

 

could be^

 

Now if he had an arc-eye hawkfish, then he should be be worried.

 

The tangs...killing or stressing the other tangs to the point of death...especially with the Naso and Clown...if they were together since they are both agressive species of tangs.

Clowns, incredibly territorial especially if there is a dominant breeding pair...

Gobies, some of them are agressive towards other fish with similar body types...

Other than you nitrites being "high" ( I use quotes because I have "high" nitrates and have absolutely no problems with my fish making "high" a relative term), there is nothing that suggests your water is causing the problem.

Aren't Mandarins territorial towards similarly shaped fish as well?

Also, correct me if I am misunderstanding you, but the shear number of fish could be a big issue if all of those were in a 125 at the same time.
I am far from the tang police, but some of the tangs you have listed are big water fish...and a 125 is borderline too small for them.

 

Quotes from Dr. F&S

Naso Tang: "It is aggressive towards other tangs, but peaceful with other fish in the tank." Minimum tank: 125gal
Clown Tang: "It is aggressive towards other Tangs, Surgeonfish, and fish with similar body shapes or feeding patterns." Minimum tank: 150gal
Scopas Tang: "It is aggressive towards its own species or tangs in general, and best kept with only one per tank." Minimum tank: 70gal
Kole Tang: "It is aggressive towards other Tangs, therefore, it is best to only keep one per tank." Minimum tank: 70gal

One or even 2 of those tangs would be OK in a 125 at the same time...but I would be concerned with adding even one more as they could become agressive towards each other...

Mandarins/Dragonets (Scooter Blenny)...I know these aren't on your list of dead fish but having 3 conspecific species in one tank...could eventually cause issues. Just keep an eye on them...

Gobies:
Sand Sifting(Twin Spot and Sand Sifting are the same thing): "It will rarely act aggressively towards other fish, but is territorial, and will fight with its own kind unless they are a mated pair."
Six Spot: "It rarely will become aggressive towards other fish, but is territorial, and will fight with its own kind unless they are a mated pair. "
Clown: "It is best if Clown Gobies are kept with other docile species."

Personally, I love a well stocked tank as they tend to be far more entertaining to watch so take what I put above as no means a criticism of what you have in your tank. Take it as possible suggestions as to what may or may not be happening...

 

I was at Chris's last week and his tank looks great. The ricordias I got from him are doing very well, thanks Chris. I went over many things with him to try to find the cause of this. The only thing I could think of at the time was maybe current leakage from a powerhead or other device. Having never knowingly delt with this I didn't know if this could be the cause or not.
But now that I see his Params .... why are nitrites elevated??? What am I missing here. Nitrate has to be really high to cause health problems in fish while Nitrite is extremly toxic to fish for any extended period. If I remeber right Nitrite is measured with the same scale as Nitrate which makes this reading quite high. With a proper nitrifying bacteria load your Nitrite should always be 0. I feel I am missing something since others didn't point this out stronger. Why are the aerobic bacteria not turning this into Nitrate? And with that much of a bio load how are you keeping your Nitrates at 0 with only bi-weekly water changes (which is good) and some macro algae. I know I am not the only one that has had severe problems keeping Nitrates low but Nitite has always been 0 in my tanks including freshwater.
Chris, are those Nitrite and Nitrate readings from good test kits? Something really seems wrong here. Sorry if I have completly missed something here, I am very tired.

 

I have to agree. There should really be no reason for the nitrites to be elevated, unless this was a typo and he meant nitrates.

Also for that large of a system I would definitly be looking into a better skimmer. If you have a 75 gal. sump I would think you would have room for something much better than a bakpak in there. You may think your bakpak is good but wait until you try something better! There are some really good ones out there now that perform good for a decent price. A lot of people on here are running the Octopus skimmers which seem to be pretty good.

I've heard of Clown tangs being super agressive. He may be irrating the other fish when you're not looking. Are the new fish always hiding until they die? Or are they out in the open? I bought a flame angel and my Powder Brown Tang pretty much killed it. It hid all the time and if it did venture out for a little food the tang would chase it right back into the rocks. After that I started adding all my fish after the lights were off and I never had another problem.

 

This might be a stretch too but what is your salinity at? I've heard of people putting fish in there tanks and having them die because there salinity is to high. The fish you currently have are used to it being high because they've went through the gradual change but the new ones can't tolerate it? Just a guess.

 

Thats quite a setup. It sounds to me like your nitrate is switched with your nitrite... If your nitrite was that high i dont think that you'd have any fish alive for more than a couple days.
Whats your akalinity? Once my akalinity was pretty high and it stressed out my fish & clam pretty bad.
What brand of RO unit do you use? A college chemistry proffessor that i know did silver nitrate tests on some local RO distributers and found that some of the tested water was high in chlorine and toxic to fish.

 

Chris,
How large are your water changes every two weeks? I have to agree with Matt though, get a better skimmer, even a coralife would be much better. You have too nice of a tank to trust it to a backpack. Sorry, I am sure you realize the backpack has a very low reputation. But that shouldn't be what is killing things off.
Also, what is your salinity again? I think you told me 1.025 when I was there which is good but ..... are you using a hydrometer or refractometer? Hydrometers will tend to be very innacurate after time or even when new. Both of mine were about .005 off before I calibrated them. Randy Holmes-Farley has a very good article on easily calibrating these at home with RO and table salt. I did this before buying a refractometer and marked 1.026 with a permanent marker since that is where I keep my reef. When I got the refractometer everything is right on so I use the hydrometers to mix and the refractometer to watch my system. Just a thought stemming from what Matt said.