Rapid fish loss problem - can anyone help?

[noops]

Had a tropical tank up and running 5 years ago for three years and never had any problems with it - left the tank empty for 2 years and have recently started it up again. Its a 60l corner tank with fluval 2 filter with new sponge.

The same gravel was used and washed thoroughly first and the tank was set up for a week before fish were introduced to de-chlorinate etc. We introduced 7 neons and 6 tetras to start with and they were fine. A week later we took a water sample into our local fish shop and they said all the levels were high and recommended we buy some ph7 stuff which we did and also that we do regular water changes.

After a further week the fish were still fine and we bought our own test kits (pH, ammonia, nitrate and nitrite) and the levels were a lot better - however the nitrate seemed to be towards the high end of 'okay' at 20mg/LNO3.

We then added more fish (2 black widows, 2 silver mollys, 2 gouramis, 4 male guppys and 3 bumblebees - the supplier ensured this would be ok) and a lobster and the problems began a few days later.

Our fish are slowly disappearing. Sometimes we find remains and sometimes we dont - we know the lobster is eating them but we think only when they are dead as he doesnt seem agressive towards them. A few guppys and neons have disappeared completely, is it possible he has totally eaten them overnight or is this alien abduction?!

One of the black widows (largest fish in tank) seems quite agressive towards the other fish, chasing them around quite a lot. Could they be overly stresed because of this? And is there anything we can do about it?

One of the remaining neons has a single white spot on his head but other than that the fish seem fine apart from one of the tetras who occasionly swims on his side.

Every night the fish seem fine and we're regularly checking the levels and according to our test kits they are pretty near perfect but when we wake up in the morning we are a few fish missing.

In the last 3 weeks we have lost 4 neons, both gouramis, 1 tetra, 1 bumblebee and 3 male guppys and a sunset platty and dont know whats going wrong.

Does anyone know what we can do?
Thanks.

 

[noops]

Also forgot to add that when we got the levels tested originally the shop owners recommended that we add aquarium salt to the tank. So we bought some and added the dosage on the packet (1 teaspoon per 3 gallons of water). This is something we didn't do the last time the tank was set up.

Could this be the problem?

 

[snowyangel]

First, one week is not nearly long enough for Cycle to take place. When your tank is cycled, there should be ZERO ammonia and ZERO nitrite, not alittle of each. Any amount of ammonia is deadly to a fish, same with nirite(just not as lethal). If these are still present int he water and you add fish, they will suffocate the fish b/c they prevent the fishes blood to carry oxygen, then they suffocate, so signs of death aren't visible.
I don't know why they told you to buy a pH7, all that will do is neutralize the ph, not change the ammonia or nitrites. Sounds like a pointless sale to me *urge to punch store ppl*
When you added the fish with these " Pretty near perfect" levels still present, more waste(pee/poo) is created, therefor creating a more deadly environment. Adding 13 fish is ALOT to add at once, maybe if you only started out with say 3 neons, you could've worked from there, but that many fish will send your levels rising and your beneficial bacteria can't convert it all to safe levels of nitrate(still following me here?). Plus, when you start purchasing fish right after your done cycling, wait another week before purchasing, then buy another 3 fish.
Now about your fish. Always research your fish before buying them, that way you know what they're adult size is, their compatiblity with other fish, what ones need to be in schools of 5 or more, etc. I can tell you one sure problem, your gobies. They don't even like freshwater that those other fish prefer(your store should of told you that). They like brackish water(water high in hardness, and half salt, kinda like diluted salt water). Then there's black skirt Tetras, they are semi-aggressive, and will especially nip nice flowing fins like that of your male guppy. Having them in bigger schools(try 6?) will reduce agression, but then your tank would be even more over stocked. Your mollies love salt in their water, but neons and black skirts do not b/c they're sensite to salt and meds.
Your finding pieces of your missing fish, probably b/c they either die from ammonia or nitrite posioning or agressive fish causing them stress and ripped fins. Most dead fish will be eagerly devoured by any bottom feeder(like your lobster) and other fish, hence bits and pieces you find.
I don't want to write a book here, so please research all your fish for their conditons and what environments they need. Then keep doing daily 15% water changes to reduce those levels and to make sure they don't rise. Keep adding the salt(it helps aid aggainst the poisoning) but not full dosages b/c the black skirts and tetras remember. Keep testing every day for ammonia and nitrite until they reach zero.
I hope i didn't yell at you, just some stores like yours really frustrate me.
Good luck and kick your lfs in the butt for me, k?

 

[MollyPlatyLuvr]

Your problem lies in that you added too many fish, too quickly. You also have aggressive fish in with community fish, and fish that prefer brackish water in with those who can't tolerate salt. Mollies, for example, love slightly hard and salty water, but they can't be in the same tank with tetras because tetras need softer water.

You didn't allow your tank to cycle. This has nothing to do with dechlorinating the water. You need beneficial bacteria to build up before you are ready for a full fish load.

Your tank sounds like it's starting to cycle, and that's why fish are dying off. Don't add any more fish until those levels get back down to zero! Until levels stabilize, I'd suggest testing the water daily. You need to test ammonia levels, as well as nitrite, nitrate, pH, alkalinity, and hardness. Invest in a good quality testing kit, and LEARN TO USE IT. The liquid kits are more accurate than those dip strips are.

Until the levels are down to zero, DAILY partial water changes are recommended. (about 15-20% depending on who you talk to)

(edited to add info about fish compatibilty and water changes)

 

[FishDan]

In addition to the potential cycle issue, the lobster could very well decimate a fish tank's population. Especially at night when the fish are less active. The lobster will eat anything he can get at, and that would be most fish, again, especially when they are least active. Your losses could be a combination of high ammonia/nitrites and the lobster. You should ensure that your ammonia and nitrite levels are 0, that is the only good number for these. And 20 ppm of nitrate is hardly bad at all, as nitrates are far less lethal than the other two (ammonia and nitrite).

After your tank cycles completely, and when you add new fish, do not add too many at once. Add a few at a time every couple of weeks. This allows the beneficial bacteria to catch up with your fish load.

\Dan

 

[noops]

Thanks very much for all the feedback - its much appreciated.

We guessed that we had put too many different fish in the tank at once when they started disappearing but werent sure. We were asking the advice of the shop as it did seem quite a good one although its now been proved otherwise and we'll go elsewhere from now on. They probably just wanted to sell as many products and fish as possible and werent bothered for their welfare. Guess we should have done more research on the internet first.

We do have a liquid test kit and the levels are all at zero or near to it except the nitrate which was near 20 although that is still in the recommended limits. We'll keep testing and doing partial water changes though and hopefully it will all be okay. And definitely not add more fish yet.

Thanks again - glad we found this website!

(Ps. the lobster shed his skin last night!)