please help, i have introduced new fish and now my fish are dying.

i have a large (120 liters) fresh water tropical fish tank, a year old.

i have been introducing fish about 4 at a time over the past year. so far i have;

1 silver droller, 3 Japanese fighters (1male), 2 silver sharks, 6 neon tetras, 3 glow light tetras, 3 silver tip tetras, 1 dwarf gourami, 2 hoplo catfish,1 mollie,3 pepped cory, 1 blind cave fish,1 swordtail, 3 kuhli loaches, 4 aquatic frogs, 2 shrimp and 1 fantail shrimp

5 days ago i got more fish from my usual shop; 6 halequin teras , 3 corys and 1 raphael catfish.

on day 3; 1 harlequin terta died, 1 neon tetra and 2 loaches. none had any visible abnormalities (apart from being pale which i guess is normal after death). i tested for ammonia and nitrate both resulted perfect levels. and did a 50 % water change (with treated water) and added the usual dose dose of black water extract. i phoned the shop , the regular guy i deal with wasn't there and his assistant said that it can just happen sometimes and there's nothing i can do. there are no visible signs of infection.

on day 4; i can only see 3 harlequin tertas ( 2 are missing), absolutely no were to be fond, iv checked usual hiding places. and a hoplo catfish dies.

on day 5(today); still only 3 harlequins visible. 1 female Japanese fighter dies. she had what i think was pop eye? big bulging eyes, as if bubble underneath the eye sockets. she was swimming turning round and round (turning upside down) towards the bottom. before i got to isolate her she died, looked healthy about 4 hours ago.both females have been looking a little overweight last couple of weeks .is her infection due to the probably dead tertas contaminating the water? but i really cant find them!

iv been feeding the frogs blood worm at night when i turn the lights off, because they are normally hiding so i cant hand feed them. i got a new batch from the same shop 5 days ago but they told me it couldn't be the blood worm .i think the fish have put a little weight on propablly eating the blood worm so shop advised me the feed the fish every couple of days as opposed to everyday.

i noticed on day 3 the temperature had fallen to 24 degrees ( normally 26), but its remained normal since. my previous water change was 3 weeks ago (normally 30%). were i washed 1 filter and added 1 new one and changed the carbon filters. iv got a fluval filter,(which also pumps oxygen through the water.)

so far all other fish are acting normally and all look healthy. (i have noticed that about 4 times in the past 6 months when i turn the lights on the neons esp. look very pale but the restore to usual colour in about 45 mins every time, the shop said that's normal too?)

i cant understand what could be causing so many to die all at once, it must be the new fish have brought something with them? but they all looked healthy.

please advise me what to do i cant bear the thought of losing more!

I don't know much but I think you should do a water change first off. If your last one was 3 weeks ago then it is definitely due.

I would also check your water stats. You may have gone into a mini cycle from adding fish.

How did you wash the filter? If it wasn't in old tank water but in normal tap water you may have killed your bacteria which will also uncycle the tank. I managed to cause a minicycle in mine from squeezing it in old tank water as directed so could still cause a cycle.

If you are in a cycle you will need to do lots of water changes to keep the ammonia/nitriite down till it is over. I don't know much about the diseases but many will appear from poor water quality, and I doubt that water changes can do much harm until someone more knowledgeable comes along and advises you!

I have some red nose tetras which go very pale when I turn on the lights,then the colour slowly comes back. I haven't had them that long so not an expert but I think (hope!) it is normal.

This post has been edited by stupidaboutfish: Jul 14 2008, 08:28 AM

hi, thanks for your advise

iv been doing 20% water changes every day, so far it seems to have helped. wont touch the filter for now. i get the feeling that my local shop over estimated how many fish i should have in my tank and its upset the cycle.

iv also researched that neons do go pale during the hight so its completely normal!!

Your tanks severely overstocked.
Male betta shouldnt be kept together.
Silver sharks which are bala sharks need 90 gallons tanks.
Can you post your water stats in ammonia, nitrite, nitrate and ph.

hi,

iv been doing water changes and had my water tested at my shop today, everything is in good condition apart from a slight increase in nitrate, i was told to keep doing water changes.

i only have 1 male fighter.

and will be arranging to give the sharks back.

thanks for your advise.

Hi. Your problem is you are overcrowding your tank. There is not enough room for them to swim around and since there are so many, they don't let others eat. Hope this helps!

I would invest in a liquid master kit of your own as some lfs are not to be trusted.
I would think of rehoming the shark as the tank way to small for them.
Research the fish before you buy them and don't always trust the lfs.