Struggling wannabe

[0Effort]

About 16 months ago I got a new 75 Gal Tank I wanted to set up as a salt water tank. I started off reading books like "Aquariums for beginners" and such. I purchased a wet/dry filter (125) w/pump, 40 lbs of live sand and around 40 lbs of live rock. After about 3 months I purchased 10 Damsels from Alamo Aquatics (an employee recc.) to "cycle" the tank. He said as they died just leave them in the tank to help cycle it. 9 died within 3 days (#10 still alive today). Everytime I go to a store for advice, I always mention "I am new and learning". Well, 16 months after this all started, I have 1 damsel, 1 emerald crab, 2 hermits, 1 Brittle star and a cleaner shrimp that seem to be invulnerable. I have purchased many fish over this period including a yellow tang, mandarin goby, false percula (most recent), and many others... All seem to meet with the same fate.
Day 1 all ok lights off no feeding.
Day 2 all ok tank back to normal feed fish
Day 3 all ok evrything seems fine untll early evening.
fish act like they are either starving or do not have enough air.
they fight the currents and swim to the surface and then back down to the bottom for about an hour or so and then just give up and die. The Percula seemed to be eating fine the day before, so I don't really think it's a hunger problem. the fish do not lose color or anything they just pass away. I have taken water samples to 3 different places to have tested, all 3 said my water was good.
My wife and I cannot stand the thought of condeming any more fish to our tank. We know there has to be a reason for this, it is just beyond us.
We seriously thought about giving up, but we both enjoy the tank so much we really do not want to.
Any thoughts or ideas would be greatly appreciated. We just don't want to continue killing innocent sea life.
Tank Specs:
75 gal fresh/salt tank (Petsmart)
125 wet/dry w/pump (Alamo Aquatics)
Protein Skimmer (Texas Tropical)
40 lbs live sand (Forever Pets)
total of 60 lbs live rock (assorted places)
2 x 20 w Power-Glo bulbs (Pet smart)
Using Nutrafin MAX - Marine complete food
Water test kit by Aquarium Pharmaceuticals Inc.
Introduced last fish by 1/2 cup of tank water to bag every 10 mins for 1 hour prior to releasing.

Thanks in Advance

[Gator]

welcome to maast

you will definitly get some helpon maast. Whast is your temperature on your tank. aslo what type of chemicals or foods are you dosing anything you put in tank

[BA]

And salinity?

[0Effort]

Thanx Gator for the welcome.
I have not been using any chemicals in my tank.
My target Temp so far has been 80 Deg. I just doubled checked and it has crept up to 82 deg. I went with 80 as per advice from from 2 of the places I made purchases at.
The salinity is at 29 ppt.
Also I have only done 1 water change of 15 Gals as none of the water tests have indicated any problems. Should these be done no matter what and how often?
I have Bio balls in my wet/dry sump, is there anything there I should be changing/cleaning?
I usually feed approx a single layer of food the size of a quarter daily.
Everything in the tank seems like it is doing well, just not anything new I try to introduce.

BTW I have alot of small worm looking things digging around in the sand, occasionally they swim around for a few minutes, but then go back and burrow into the sand. I saw them at one store and was told that was a good sign.

[Moonrs]

I realized after the fact that I was not looking at my meter correctly. Your salt is a little low. I'm don't know if you have a fowlr or not, but the salinity probably isn't killing the fish, at least right away. It's more likely some of the other perameters that the posts after this one mention. Good luck and don't give up!

[GaryP]

Hold on here. A salinity of 29 ppt. equates to somewhere between 1.021 and 1.022. That is acceptable for a fish only tank. That is not not hyper saline, its actually a little low compared to natural sea water (1.025).

I don't think salinity is your problem, however, I would recommend a regular schedule of water changes. At least once a month. There are a lot of things that could be toxic to your fish that aren't going to show up in your test kit. I'm going to send you a PM.

Gary

[CG]

Could be the damsel getting aggressive, they don't normally attack inverts so I'm guessing thats why you haven't lost any of them. What kind of damsel is it? Anything besides chromis' are very aggressive

[COBRA201]

I think is your ammonia thats killing them. Alot of the time testing can only tell you so much. also you might have alot of organic junk in your tank cause lack of cleaning. I have a 75g (reef) and i do water changes every 2 weeks (thats a 15g water change). I also clean the pad filter that gose in the wet/dry or change it if is too old.

I hope you have a very good skimmer too!!

[matt]

How about that advice "use 10 damsels to cycle the tank, and leave the fish in there when they die"

That's offensive on many levels. One, and maybe the worst, is the selling of fish with the stated intention of killing them through poor tank conditions. Two, it's very bad advice; using multiple fish to "cycle" a tank reveals a basic misunderstanding of some of the most fundamental principles of marine fish keeping; something anyone of even moderate intelligence could learn with a small bit of effort. Sometimes I wish there were licenses required to sell these animals. Please do not deal with whoever gave you that advice any more.

Regarding your dying fish, I suspect you have a series of contamination/chemistry problems, that your current tank inhabitants might have adapted to, or a fish parasite that your damsel has managed to keep at bay, but is still present in your tank. Are you sure your salinity is 29ppt, or did you mean 1.029 specific gravity? Are you using a refractometer or a hydrometer to test? Whatever it is, you should adjust it slowly to about 35ppt, which is a specific gravity of around 1.025 at 80o. Please understand that most plastic swing arm hydrometers are innacurate.

Okay, then you check for calcium, alkalinity, ph. (in the morning before the lights come on) You want calcium in the 400 range, alkalinity in the 2.5-4.0 meq, and a ph of 7.9-8.2 in the morning. No need to test for copper if you have living invertebrates. You might also remove any remains of dead fish if there are any left. Make sure there is no chlorine in your water. BTW, this is assuming there are no nitrogen problems (ammonia, nitrite, nitrate)

Then you should remove the damsel and leave the tank fish free for at least a month; preferably longer. Maybe aquatic warehouse will take your damsel; I wouldn't expect any money for it, but they might agree to put it in their quarantine system. In any event, you'll get introduced to a fish store where they won't give you irresponsible and wildly wrong advice.

During the no -fish time, you could change a lot of water, making sure you carefully match the salinity, ph, calcium, and alkalinity of your tank with your replacement water. Use R.O. water. Allowing your tank to stay fish free for this long should eliminate the possibility that you have a parasite living in your tank. Finally, when you re introduce fish, buy them from a dealer that quarantines fish for a couple of weeks; maybe start with a pair of tank raised clowns. A big part of your problem might be buying sick fish.

The worms in your sand and the survival of your shrimp and crabs means that not all is wrong in your tank. Good luck, and welcome to MAAST!

[adamRS80]

Welcome to maast. plenty of us are wannabes compared to some of the experts on this forum. I'm sure you'll get everything figured out real fast now. Sometimes stores prey on beginners which I hate to say, but they never should have sold you some of those fish. It's hard for most people to keep mandarin gobies because they require an established tank with lots of live rock. When fish are dying the solution isn't replace them with another, but saying no means not making a sale which takes precedence over giving proper advice in some stores. I think almost everybody has had this experience starting out. Find a good store that has people who care about doing the right thing. check out the vendor experiences forum to get an idea of where to go from here. good luck with everything.