Sudden death of my guppies

[Severine]

Hello, everyone, I’m new to this forum, so please dont be harsh to me, as I’m still learning new things i havent known before

I have a 200 l / 50 g blackwater tank, there are:
9 kuhli loaches
7 ottos
7 african dwarf frogs
8 sterba corys
8 guppies (which the 2 of them were dead several days ago)
50 neon/cardinal tetras (you read it right)
5 celestial pearl danios
Lots of small branches & driftwood , and amazon frogbits was the only plant i have in this tank (they cover almost all the water surface so just a little light that’s able to pierce to the inside of the tank)

i know this is a heavily overstocked tank, but im pretty sure that this tank is fully cycled and no sign of continuous fish deaths for all this time.

my question is, i had 2 identical guppies with dark navy tails, 1 of them went missing, and 1 of them was found dead below a driftwood (luckily i had found it soon enough).
before he died, he had a reddish spot on the tail, some thing like a “bloody mark” or sort of things like that i dont understand. What is the kind of the disease and was it the cause of the death?
im pretty sure the missing one was dead and got eaten because ive searched anywhere and i cant find him.

other fishes seem to be okay and active tho.
If you have an idea, please kindly help, great thanks in advance

 

[kwi]

Can you tell us your water parameters?

 

[Colin_T]

Any chance of a picture of the fish?

Red marks on fins can be physical damage from being bitten by something or damaging the tail on something in the tank. It can also be a bacterial infection but without seeing the fish, it's impossible to say.

If more fish develop the same red patch, then post some clear pictures of them on here straight away.

 

[FishBearer9845]

The only way to be sure the parameters are good is through a water test kit. The API master freshwater is brilliant.
How long have you had the tank running, when did you add fish and how many water changes do you do and the percentage

 

[Severine]

Can you tell us your water parameters?

Im sorry but i dont have any kit yet, im about to get one. Is there any kit that able to test all parameters in one package; water hardness, ammonia & nitrate level, and acidity?

 

[Severine]

Any chance of a picture of the fish?

Red marks on fins can be physical damage from being bitten by something or damaging the tail on something in the tank. It can also be a bacterial infection but without seeing the fish, it's impossible to say.

If more fish develop the same red patch, then post some clear pictures of them on here straight away.

Too bad i didnt have the chance to get the pic, but when i found the dead one, the tail seemed more “infected” by the red spot, ill try to search for a pic in the internet that resembles the condition of my guppy tho, thanks for the answer!

 

[Severine]

The only way to be sure the parameters are good is through a water test kit. The API master freshwater is brilliant.
How long have you had the tank running, when did you add fish and how many water changes do you do and the percentage

The tank started in june 1st and I got all the bacteria starter and driftwoods. After 2 weeks i added the fishes gradually, and everyone was okay, no sign of massive deaths at once. Ive been changing 50% of water every 2 weeks using distilled water. I’d be better searching for the kit right now!

 

[Severine]

Any chance of a picture of the fish?

Red marks on fins can be physical damage from being bitten by something or damaging the tail on something in the tank. It can also be a bacterial infection but without seeing the fish, it's impossible to say.

If more fish develop the same red patch, then post some clear pictures of them on here straight away.

this is the pic that pretty much resembles what my guppy experienced before.

so this is the chronology:
I had 2 identical guppies with brilliant navy tails, they were pretty active and i could see through their tail when it was pierced by the light, very beautiful dark blue in gradient.
one day i noticed one of them was missing and i couldnt find him, ive searched in the entire tank and below the driftwoods.
i thought he might be eaten already by other members of the tank, so I stopped searching any further.

The next day, i noticed the red spot on the tail of the other guppy, i had experienced the same thing with the same guppy in a smaller tank earlier (i moved these guppies to the bigger tank a month earlier and they had been doing great)
(In the smaller tank, the same red spot occured but cured no more than a week as well)

the problem is, since ive known this problem before and i thought that the fish would cure, he died the next day.

 

[kwi]

Im sorry but i dont have any kit yet, im about to get one. Is there any kit that able to test all parameters in one package; water hardness, ammonia & nitrate level, and acidity?

The API master kit does all but hardness and is good value and easy to use. They do a seperate hardness kit.
You can get test strips but these are known not to be as accurate but can give you an indication of where things are. They're relatively expensive per test compared to the liquid test kits.

 

[itiwhetu]

You say this is a black water tank. So I will assume acid /soft water guppies don't particularly like that and when I have seen this type of bleeding on guppies and other live bearers have always put it down to the water not being suitable. They may have been raised in an Alkaline system and then haven't adapted to their new tank.

 

[Severine]

You say this is a black water tank. So I will assume acid /soft water guppies don't particularly like that and when I have seen this type of bleeding on guppies and other live bearers have always put it down to the water not being suitable. They may have been raised in an Alkaline system and then haven't adapted to their new tank.

Thanks for your reply,mate. When i had them all at my smaller tank (clearwater) they seemed not as active as they do in this blackwater tank tho, some of them often lied on the bottom and hid a lot. I was thinking that it could be happier for them to join a large community, as some of them were still juveniles, now they grow beautiful colorful tails, I’ll take a pic when i have the time later.
is there any sign or possibility of uncomfortness even though they are growing beautifully?

 

[Severine]

The API master kit does all but hardness and is good value and easy to use. They do a seperate hardness kit.
You can get test strips but these are known not to be as accurate but can give you an indication of where things are. They're relatively expensive per test compared to the liquid test kits.

Dude. Wow. I just searched for the API kit that you mean, it costs around USD 55 here . Do you have any idea how long it can be used if i test the water parameter once a week?

 

[itiwhetu]

Was there a temperature difference between the two tanks

 

[kwi]

Dude. Wow. I just searched for the API kit that you mean, it costs around USD 55 here . Do you have any idea how long it can be used if i test the water parameter once a week?

There's 800 tests across 5 parameters. Compared to their test strips which come in tubes of 25, and you need to buy 2 seperate tubes as the 5in1 dont do ammonia, it's actually cheaper. And then you can buy the tests individually to replenish the ones you've used up.

 

[Severine]

Was there a temperature difference between the two tanks

Nope. Maximum difference is 1 degree C. Theyre both constantly at 28-30 C. It’s tropical area here so i dont use any heater, if it gets too hot (to 32 C) i turn the fan on to keep it stable. But most of the times, theyre both at the same temp.