Losing Fish

Hello Everyone,

Started losing fish about a month ago and I am getting kinda clueless what could it be.


1. Water parameters. (ammonia, nitrate, nitrite, PH, temp', Hardness etc)
These should be all good, API liquid test kit shows:
0 Ammonia
0 Nitrite
10ppm Nitrates
Ph 8.0
28 celsius

2. A full description of the fishes symptoms.
Lost 2 platies with the following symptoms.
Fish wasting away, sitting at the bottom lethargic. Fins clamped. Gills and mouth moving rapidly. Then they stop eating and just die.

Then there is the Danio that I have attached pictures about.
Bloated, behind his right side gill it is missing scales? Or maybe flesh hard to tell. Gill on one side is red above that there is a lump and scales are sticking out.
He is still eating and swimming actively.

I don't think he will make it.


3. How often you do water changes and how much.
2x a week 30% each time.
Also running two filters recently, one with carbon the other one with nitrate + silicate filter (fluval can't remember the name).

4. Any chemicals and treatments you add to the water.
Suspected internal parasites tried both flubenazol and levisamol.

5. What tank mates are in the tank.
4 Danios, 8 adult platies, 5 baby platies and a betta.

6. Tank size.
200L
7. Finally Have you recently added any new fish?
No.

Hi there! First thing I noticed was the temperature was quite high which I'm assuming is to accommodate the betta, danios prefer something much cooler. Also, your pH is OK for the platies but your betta prefers something between 6 and 7.

Have you noticed what colour poop is coming from the fish? Could have a worm issue?

CaptainBarnicles said:

Hi there! First thing I noticed was the temperature was quite high which I'm assuming is to accommodate the betta, danios prefer something much cooler. Also, your pH is OK for the platies but your betta prefers something between 6 and 7.

Have you noticed what colour poop is coming from the fish? Could have a worm issue?

Click to expand...

Thank you for your reply.

The platy that is wasting just does a
Transparent poop, due to not eating.
I haven't actually seen the danio's yet.
I suspected internal parasites that's why I tried Flubenazol and later levisamol.
Maybe one of those worked and the danio is having a secondary bacterial infection?

I was keeping the Danios on around this temperature since I got them about 4-5 months ago. Partly due to the flat being warm over summer partly the platies and betta being added later. They did not seem to mind it.

A pH of eight is too high for most freshwater fish.

If your treatments for internal parasites has not worked you could try treatment for internal bacteria infections.
Make sure you remove the carbon to allow any treatment to work.

I recommend doing 1x 60% water change rather than 2 at 30% - the pollution will be reduced a lot. I also recommend getting the betta it's own tank - 30 or 40 litres with R/O, distilled or clean rain water as -
a) they are solitary fish and b) London water will have a high GH as well as the high pH which is not suitable for bettas.

itiwhetu said:

A pH of eight is too high for most freshwater fish.

Click to expand...

I don't know. Most of the articles I have read about pH say that as long as there are no changes in the pH it should be fine.
Mine is stable. Is it not ideal? Arguably not but it is not what killing my fish I think. I could be wrong though.

Okidoki said:

I don't know. Most of the articles I have read about pH say that as long as there are no changes in the pH it should be fine.
Mine is stable. Is it not ideal? Arguably not but it is not what killing my fish I think. I could be wrong though.

Click to expand...

yeah 8 ph is like african chiclid zone
like 7-7.5 is the meetup for most fishes
could stress the danio out and other soft water fishes

try api general cure soaked in fish food works for me

the pH has nothing to do with the red on the danio. that is a bacterial infection.

no idea about the other fish, can't be bothered reading anything due to the heat.

Transparent poop, fins clamped, gills and mouth moving rapidly, missing scales - nomatodes, or gill flukes.
At least that's what my fish looked like when they had one or both of those parasites.