Fish Dying On An Almost Daily Basis...no Idea Why!

[Jinkz]

Hi all.

Hoping someone can give me a bit of help here as I've encountered a problem with my 100ltr planted community tank and it's a bit of a head scratcher.

OK where to start....

Tank = 100ltr Bow Front
Substrate is Seachem Flourite dark with 2mm black quartz gravel atop.

Tank inhabitants (at this moment) as follows;

• 2 x Male and 2 x Female guppies
• 1 x Harlequin Rasbora
• 1 x Male Black Mollie
• 1 x Female Swordtail
• 1 x Male and 1 Female Betta
• 2 x Male Leopard Corydoras
• 4 x Female Leopard Corydoras
• 1 x Albino Bristlenose PLeco
• 1 x Male and 1 x Female Danios

Starting off around 2 weeks ago I received a package of plants from a UK retailer. Washed and planted them in the tank, so far so good. I should add that I already had a few plants in there from my 300ltr tank. I also have a piece of mature bogwood in there and a piece of mopani with java moss colonising it. Then all of a sudden around a week or so ago I started losing fish at the rate of 2 - 4 per day. There were no outward signs of any disease either on the dead or still live fish. Naturally I tested the water and was surprised to find that all the parameters were ok...as follows;

1st April

• PH: 7.6
• NH3: 0.25ppm
• NH4: 0.25ppm
• NO2: 0ppm
• NO3: 20ppm

Results to yesterday (testing almost on a daily basis) were almost always the same.

Then last Thursday late afternoon the ballast on my light blew and due to having numerous things to do I only got around to changing the light yesterday. Meantime I lost more fish so again tested yesterday, as follows;

1st April

• PH: 7.6
• NH3: 0.25ppm
• NH4: 0ppm
• NO2: 0ppm
• NO3: 40ppm

Soon as I seen the ammonia was higher I immediately changed 50% of the water and tested again and it had came down to 20ppm. Came home from work this evening and I had another two dead Rasboras and another dead female guppy. In all I've lost 8 Rasboras, 1 Molly, 1 Swordtail and 6 guppies.

This was a tank I set up for my 8yr old as she enjoyed helping me tend to my 300ltr I have in the living room so naturally she's pretty upset at so many fish dying, despite my best efforts to explain to her that sometimes fish do die but I'm now at the point where I'm really baffled by this.

The male and female fighter, the guppies and the bristlenose pleco were the first fish in the tank after I'd cycled it using mature media from my 300ltr. We then added the danios, mollies, swordtails and rasboras, then finally the corys. I'm around the tank every morning and evening and I've never seen any harassment of any of the fish from others and likewise I can't see any outward signs of disease. All the fish come to me when it's feeding time and they were all eating prior to death....really can't work out what's causing it.

If anyone has any ideas I'll be more than happy to hear them.

Cheers, Tony

 

[Jinkz]

No-one?

 

[roadmaster]

You have quite a few fish for roughly 26 gallons and if the tank is newly established, then it is possible that fish died back to what the biological filter could support.I might borrow some filter material from your 300 litre tank and place it in the filter compartment of the 100 litre to help increase the bacterial colony.
A cycled tank with healthy biological filter should render zero for ammonia every day,all day.
I might also add some more plant's to help use up any excess ammonia which they are quite good at doing.
Would also assume the feeding responsibility of the fishes lest little hands offer too much food which can contribute to elevated ammonia levels.
Readings aren't bad,but as mentioned,,the ammonia should not be there, and it is possible that at different times during the day such as after feedings,the ammonia levels are higher than what you have posted.
Would also use PRIME for treatment of water before using it in the aquarium during weekly water change which in mmy view should be on the order of near 50 percent for number's of fish you have.

 

[Athena]

hi - i agree with the above that your stock level was too much too soon and your filter colony of bacteria could not cope and hence the ammonia readings. That should be zero. Also just like to add that a male and female betta should never be homed together as sooner or later they will fight and the outcome will be upsetting. They are usually only put together briefly for mating.

Keep up with the daily water changes and reduce feeding for your stats to read normal.

Regards athena

 

[Jinkz]

Thanks for the replies.

I should have mentioned in the initial post that I did cycle the tank with mature media from my 300ltr tank. The filter I'm using is anAqua One 103F which I do clean regularly in aquarium water. I usually rinse it out once a week as with the aquarium being planted it can gunk up.

I agree with stocking levels being too high but the aquarium was cycled as I mentioned and it was running a full month with only 6 guppies occupying it before any other fish were added. There should be more than enough plants in there to help break down the ammonia. I have crypts, swords, egeria densa, java moss, anubias and a few other plants in there providing plenty of greenery and cover for the fish. The plants all seem to be thriving and I've had to trim a few lately as they were doing so well. I've attached a pic of the tank.

Oh, should have mentioned that I always use Prime when doing water changes. Have been since I bought this aquarium.

Now that quite a few of the fish have died obviously stocking levels are a lot lower than they were previously so hopefully things will calm down, but regarding feeding...I really don't feed them that much. One pinch of Tetra Min in the mornings and usually 2/3 of a cube of either Daphnia, Bloodworm or Brine Shrimp in the evening. I also usually drop a couple of sinking algae wafers in each night for my BN pleco and they're always gone by morning. Obviously the corys will also help get rid of any uneaten food but I'll try scaling back the feeding for a week or so and do a few more 50% water changes to see if things settle down a bit.

Regarding the male and female betta being together. They've been together now 8 months and I've never seen one bit of aggression from the male toward the female. They just seem to ignore one another and do their own thing, although point taken. I'll look at trying to rehome the male in his own tank soon as funds allow.

 

[Athena]

Nice pic, Jinx.

Re the bettas, yes I've heard of other people who have housed the male and female together ...(ahem...speaking from past experience when I didn't know better)and for months they seeme fine, then suddenly one day all hell breaks loose.

I almost lost my male betta when I came home to find they had been fighting and the female had ripped the poor male of all his glory. He literally had no finnage left (less than a female would have) if you see what I mean. I quickly rescued him and put him in a little hospital tank. Seriously thought he would die but with lots of care and medication he pulled through and lived a further 3 years (his fins grew back)!

When that happened I researched more into bettas and realised the mistake I had made - well, it was my LFS who told me to buy "a pair" for my tank!! I had never kept bettas before and used to rely on information from my LFS as being accurate. I don't any more!

So when I come across others doing the same thing, of course it worries me. Hope you don't mind. Just that when you said it's your daughter's tank I thought, oh dear, wouldn't want to see her upset even more. I guess if you can't get a separate tank you could always get a tank divider to cordon off one end of the tank for one of them.

Also, I'd keep an eye on that black molly, too, as they can get a bit boisterous/bullyish at times and start fin-nipping the male betta and guppies.

All the best - Athena

 

[Jinkz]

Nice pic, Jinx.

Re the bettas, yes I've heard of other people who have housed the male and female together ...(ahem...speaking from past experience when I didn't know better)and for months they seeme fine, then suddenly one day all hell breaks loose.

I almost lost my male betta when I came home to find they had been fighting and the female had ripped the poor male of all his glory. He literally had no finnage left (less than a female would have) if you see what I mean. I quickly rescued him and put him in a little hospital tank. Seriously thought he would die but with lots of care and medication he pulled through and lived a further 3 years (his fins grew back)!

When that happened I researched more into bettas and realised the mistake I had made - well, it was my LFS who told me to buy "a pair" for my tank!! I had never kept bettas before and used to rely on information from my LFS as being accurate. I don't any more!

So when I come across others doing the same thing, of course it worries me. Hope you don't mind. Just that when you said it's your daughter's tank I thought, oh dear, wouldn't want to see her upset even more. I guess if you can't get a separate tank you could always get a tank divider to cordon off one end of the tank for one of them.

Also, I'd keep an eye on that black molly, too, as they can get a bit boisterous/bullyish at times and start fin-nipping the male betta and guppies.

All the best - Athena

Thanks for the info and advice Athena. I do appreciate it.

Actually was thinking of returning the black molly and swordtail to my lfs as they're each on their own and should be with more of their own kind so I'll probably take them back and get a couple more danios. Love watching them swim into the filter current. They're so lively and perky fish. A joy to keep.

I've just now done another 50% water change but had a pretty stressed day at work and couldn't really be bothered sitting testing the water. I'll do it tomorrow and post the results.

 

[roadmaster]

It sounds as though you cycled the tank with or without six guppies using borrowed material from 300 litre.If you placed the borrowed material in the 100 litre and added the six guppies directly,then perhaps bacteria was enough to process the waste from the six guppies.Two or three fish added every ten days after that, would have perhaps been fine.
If however, more fishes were added more quickly, and in greater number's,the bacteria may not have been able to process the increase in ammonia produced by numerous fishes quickly enough, to prevent a spike in ammonia or nitrites and scenario mentioned earlier could be possibility.
Bacteria develops in direct proportion to the food available (fish waste,fish foods) and bacteria increases, or decreases accordingly along with other factor's such as pH,temp,and surface area available.
If you place a bunch of seed material in a tank with few fishes,bacteria will grow,decrease,to the amount of food present.If you place not enough seed material for the number's of fish added along with foods offered to same, then ammonia or nitrite spike would/could happen and go undetected until fishes began to show effect's.Many folks are confused sometimes, and they add the seed material and either wait too long to place a few small fish in the tank or offer fish foods to keep the bacteria fed,,or they add too many fish too quickly without giving the bacteria (good kind) a chance to increase slowly,gradually.
Could also be as was suggested,,something was introduced to the tank via new fish, or through accident that killed the fish.
Have seen your tank and believe it would take much more plant mass to make possible ammonia spike or nitrite spike of little concern given the number's of fish but it is only my opinion.

 

[Jinkz]

It sounds as though you cycled the tank with or without six guppies using borrowed material from 300 litre.If you placed the borrowed material in the 100 litre and added the six guppies directly,then perhaps bacteria was enough to process the waste from the six guppies.Two or three fish added every ten days after that, would have perhaps been fine.
If however, more fishes were added more quickly, and in greater number's,the bacteria may not have been able to process the increase in ammonia produced by numerous fishes quickly enough, to prevent a spike in ammonia or nitrites and scenario mentioned earlier could be possibility.
Bacteria develops in direct proportion to the food available (fish waste,fish foods) and bacteria increases, or decreases accordingly along with other factor's such as pH,temp,and surface area available.
If you place a bunch of seed material in a tank with few fishes,bacteria will grow,decrease,to the amount of food present.If you place not enough seed material for the number's of fish added along with foods offered to same, then ammonia or nitrite spike would/could happen and go undetected until fishes began to show effect's.Many folks are confused sometimes, and they add the seed material and either wait too long to place a few small fish in the tank or offer fish foods to keep the bacteria fed,,or they add too many fish too quickly without giving the bacteria (good kind) a chance to increase slowly,gradually.
Could also be as was suggested,,something was introduced to the tank via new fish, or through accident that killed the fish.
Have seen your tank and believe it would take much more plant mass to make possible ammonia spike or nitrite spike of little concern given the number's of fish but it is only my opinion.

Thanks for the comments roadmaster.

I started cycling the tank with noodles and some sponge from my 300ltr tank and left it run for 3 days before putting the guppies in. I then added the 6 guppies and waited a week to see how things would work out and as everything seemed fine and my water stats were ok, I then added the pair of bettas. Again waited a week and again all was fine. Then my wife and kids came home with 7 Harlequin Rasboras, 2 black mollies and 2 swordtails and we added them. Again things seemed fine so I then moved my BN pleco over from my 300ltr tank to the 100ltr and all those fish were in the 100ltr for around a month without any issues. I then planted the tank out more than what was in it and added 6 leopard corys but with hindsight I now realise I overstocked the tank and put too much burden on the filter also.

Tank's a lot less populated now obviously after all the deaths and I won't be running out and buying a load more fish but I'm still wondering if there was something else that triggered this. My ammonia was never over 40ppm in any readings I took and I took a lot of readings. I done a little cleaning last night while I was doing the water change and started thinking about this and whether maybe some ornament leeched something into the water. The only things I have in the tank which are not "natural" are a plastic "shipwreck" boat which my pleco uses as his cave and a small plastic tree, which broke last night I removed anyway. I can't see it being something from the shipwreck as these things are sold all the time by pet shops and all the materials inside should be inert and neutral....still, got me wondering.

 

[roadmaster]

I hope things will be fine, but might consider a small tote or tub for makeshift quarantine tank for new fishes to reside in for a couple weeks were it me. Would need a small heater and sponge filter(or daily water change), but could save money in fish loss,medications.