Need help with dying panda corys

[Wolfgangs246]

Hi all,

I'm having some trouble with my tank and I can't seem to identify the root cause.

Background:
I have a 1.5x1.5x1 (tall) tank which I use for keeping panda cory's plus a few survivors from an older tank. the current occupants are:
- 6-7 panda corys
- 2 rummy nose tetra,
- 2 assassin snails
- assortment of shrimp.

Problem:
I've been consistently losing 1 panda cory approximately every 2-3 days. the symptoms start off with sluggish movement and sometimes darting closer to the surface, but they never take the signature 'gulp' of air. They just dart upwards but then dive again before they reach the top. Eventually the sluggish movement gets worst and soon the fish doesn't even seem able to swim around the tank and I find them dead.

Can anyone else identify what could be the cause? Because the cory's are dying one at a time, I'm not sure if it's a disease or if there is some bullying going on in the tank. Both full grown adults and younger pups have both fallen victim to this.

[ren_hao]

Was your filter from the older setup?

[Wolfgangs246]

This was a new filter, but I took some of the old filter media from my older tank, plus did the necessary cycling. Plus I've been changing approx 50% water weekly for the last 2 weeks.

[tetrakid]

This was a new filter, but I took some of the old filter media from my older tank, plus did the necessary cycling. Plus I've been changing approx 50% water weekly for the last 2 weeks.

Many will not believe this, but such a small tank is not enough for so many fish. For that size tank, I will only allow 2-3 fish, preferably of the same species, or just one betta. The snails are okay, though. This is the most common mistake.

[tetrakid]

This was a new filter, but I took some of the old filter media from my older tank, plus did the necessary cycling. Plus I've been changing approx 50% water weekly for the last 2 weeks.

Many will not believe this, but such a small tank is not enough for so many fishes. For that size tank, I will only allow 2-3 corys, preferably of the same species, or just one betta. The snails are okay, though. This is the most common mistake. It's hard to maintain a bio-balance in such a crowded small tank.

[Wolfgangs246]

Many will not believe this, but such a small tank is not enough for so many fishes. For that size tank, I will only allow 2-3 corys, preferably of the same species, or just one betta. The snails are okay, though. This is the most common mistake. It's hard to maintain a bio-balance in such a crowded small tank.

Are you seriously suggesting a 50L tank can only hold 2-3 cory's or 1 betta fish?

Can anyone else verify what tetrakid is saying?

[GHD97]

1.5x1.5x1 feet?

The thing about tall tanks...their base area isn't very big...this is a serious consideration when keeping bottom-dwelling fish like Corys...

But since I keep my fish in 50L tanks also... The base area is really important...fish in their natural habitat swim forward...most do not swim up and down continuously so...the living space available for fish is really quite small...

Your stocking levels should be fine as long as there aren't too many shrimps...so I guess the panda copies are just stressed with the cramped conditions...

For your tank...4corydoras(bottom dweller)
Rummy nose tetras(they need to be in groups of 5 to feel safe)( midwater dwellers)
OR
1Betta fish
You can keep the Cory's with either a Betta or tetras

I agree tetrakids suggestion would give very good water quality the corydoras need...but no one likes a empty looking tank check your dead panda Cory's for any symptoms of sickness

[tetrakid]

Are you seriously suggesting a 50L tank can only hold 2-3 cory's or 1 betta fish?

Can anyone else verify what tetrakid is saying?

Strictly speaking, fish can survive as long as they are in some water, ie. even in very small tanks.
However, in a fish tank (which a restricted water column) the key to healthy fish is the bio-balance within the tank. It is easier to maintain a healthy bio-balance in a large tank than a small tank. The waste output of livestock in the tank must not be more than what the bio-factors within the tank can handle in order to maintain a healthy natural balance. In LFSs one often can see a crowd of huge, healthy and happy-looking big fish in a display tank. That is because the water is maintained in a healthy state of bio-balance by the LFS's aquarium experts, perhaps with big concealed bio-sumps hidden from sight. Thus, there is no limit to how small a tank is, as long as the water in the system is maintained in a healthy balanced state to make the fish happy.

[Draka]

What tetrakid just said sounds more reasonable. Anyway more pertinent to the issue at hand it sounds like some kind of poisoning is the case here if there's no visible wounds or signs of disease. It could be anything leaching into the water or possibly some chloramines not completely neutralised. Either that or high level of organic wastes like nitrates, ammonia and nitrites; do you have any plants in?

[tetrakid]

Some time ago I had some healthy Platys which fell sick and die one by one too. It is very sim-tia (sense of loss) if you have beautiful and hard-to-get specimens. I suspect that it could be attack by hydras because at that time I was very keen to give them ang-boons (daphnia). Nowadays, I am very scared of ang-boons and also Tubifex. I only feed my fish with dried fish food,as I am lazy to cultivate brine shrimps.

[atruhfee]

If your tank is cycled like u said (ammonia 0, nitrite 0), u should probably think back, retrace your steps. Did u add any rocks or decorations before the deaths happen? did u introduce any fish ( possibly infected ones ) into the tank before it happens? did u change their diet? Sometimes it could be down to simple things like aeration, is your fish breathing heavily? (could be due to ammonia poisoning also). In my opinion I think your bioload is alright if your width is 1.5feet, should be enough for 6-7 panda cories. I've kept more cories in my 1 feet width tank without any casualty (so far, touch wood).