Fish Won't Stop Dying! Corals Thriving...

[Starfishandseahorse]

Hiya!

I have a Red Sea 750XXL 200 gallon tank that is driving me nuts. I'm new to fish, as I've always done Nano reef tanks with only coral.
All my corals are thriving in my tank right now, including my extremely finicky ones that are generally difficult to keep. My inverts look great, Urchins stealing and moving everything in sight, starfish and clams are happy, etc..

But. I cannot keep fish alive. My first wave was a a few Chromis' and 9 firefish. They all disappeared one by one. I never found any of their bodies. I waited a month before adding more fish.
I grabbed a few more Chromis and a few assorted peaceful Wrasse and a Gramma. Some of the wrasse died under various circumstances. A few of them just disappeared and I was worried that maybe one of the larger Wrasse was potentially killing them off, but then two of them started swimming around strangely before dying with visual confirmation. At the end, I lost all the wrasse and had 2 Chromis' left. I currently have 8 Chromis (including my 2 survivors) and last month I bought one firefish to try again, and sure enough, he just disappeared the other day.

At this point I've lost thousands of dollars of fish and I can't seem to figure out the pattern. The only fish I have had consistently had in the tank are Chromis. I am very careful with my acclimation process and follow recommended procedure including quarantining. I wait a few months after my die-offs to try again. I do regular 20% water changes and am meticulous with keeping my parameters stable.

All other occupants are a reef safe cleanup crew, brittle stars, tuxedo urchins, cleaner and peppermint shrimp.

My stats: 200 gallon Tank has been up and running for a year and a half. Tons of lovely Macro algaes in my refugium. More sand and live rock than is even recommended.

Temp: 76-78 degrees
Salinity: 1.025
PH: 8.2
Phosphates: 0
Nitrates: 0
Nitrites: 0

All assorted minerals and such are all within perfect range. I regularly monitor and dose supplements.

Any suggestions? I can't seem to figure out how to keep fish alive.

 

[MnFish1]

1) - could you have a predator (large crab, mantis shrimp, etc)
2) - could you have a parasite (do you QT)
3) - could the fish be fighting - its kind of 'normal' for chromic to kill each other one by one until one is left. Sometimes with Damsels, etc
4) - Do you source your fish from a trusted source? Sometimes fish caught with toxins (cyanide) look fine - then die after weeks.
5) - IME - its not uncommon not to find small dead fish in a large tank - and it could be why your snails, etc look so happy.

I would 'bet' - its disease related.

 

[Rmckoy]

Chromis are the ones that I have trouble keeping .
Its suggested to keep odd numbers but I always end with 1 before he disappears .
weird but I have learned it just be that particular fish .

fire fish are notorious carpet surfers IMO

probably not fish related but is zero nutrients accurate ?
with little fish and corals , the corals would need nutrients to thrive ?

can you describe your acclimation process ?
have you tested differences between qt and dt parameters ?

 

[swiss2]

How long do they last in the tank? Is it couple of days or weeks? Are they eating well? Until you solve the mystery I would recommend you not keep putting too many fish in the tank.

Firerefish and some wrasse are jumpers do you have a screen? See if you have can find around the tank.

Firefish are not the best swimmers. The the water flow is a fact to consider. What type of power heads are you using? And to what intensity? Sorry for the million questions.

 

[vetteguy53081]

Im going to pick on water. With coral thriving, some things will cause this:
- although could be parasites, would also be noticeable (heavy breathing, scratching, loss of appetite, dots, etc)
- My one primary suspect- High Calcium - WHAT TEST KITS ARE YOUR USING?
- HIGH AMMONIA AND POSSIBLE FALSE TEST READINGS especially if using API test kits (may be higher than you realize)
- Chromis (uronema which can produce bacteria outbreak in tank). Chromis will have red sores/patches if Uronema
- Low or High salinity
- Improper acclimation
- Inadequate oxygen
- High temperature
- Gill disease and/or lack of oxygen (one sigh is mouth hanging open rather than respirations)

 

[swiss2]

Also my rule of thumb for adding fish to a tank, regardless of how established the tank is, is one to two small fish a week for small fish and one big fish every couple of weeks. I know some people will wait a whole month to give the tank time to balance out the bio load.

 

[Mr. Mojo Rising]

Also my rule of thumb for adding fish to a tank, regardless of how established the tank is, is one to two small fish a week for small fish and one big fish every couple of weeks. I know some people will wait a whole month to give the tank time to balance out the bio load.

I was just thinking that myself, how many fish are being added at the same time? corals dont have much of a bioload, so going from fishless system to many-fish-at-once system is overloading the biofilter, in my opinion. I add fish one at a time and wait a few weeks in between, IMO, this is the right way

 

[swiss2]

Im going to pick on water. With coral thriving, some things will cause this:
- although could be parasites, would also be noticeable (heavy breathing, scratching, loss of appetite, dots, etc)
- My one primary suspect- High Calcium - WHAT TEST KITS ARE YOUR USING?
- HIGH AMMONIA AND POSSIBLE FALSE TEST READINGS especially if using API test kits (may be higher than you realize)
- Chromis (uronema which can produce bacteria outbreak in tank). Chromis will have red sores/patches if Uronema
- Low or High salinity
- Improper acclimation
- Inadequate oxygen
- High temperature
- Gill disease and/or lack of oxygen (one sigh is mouth hanging open rather than respirations)

Agree with above, with all these fish dying ammonia has to be high I would think.

 

[Tamberav]

Tank is a year and a half and 200g... corals are thriving... macro's suck down ammonia....doesn't seem like ammonia to me.

A month isn't long enough to fallow disease. Chromis dying isn't unusual...

How do you QT your fish?