Fish dropping like flies!!

Morning guys!

I'm losing my fish like crazy!

Yesterday I woke up to 2 dead neon tetras. All my parameters were OK but I done a big water change anyway, added stress coat and everything seemed fine. The remaining 3 neons were showing no sign of illness, swimming as normal, eating but I lost 2 more of them throughout the day. Checked my parameters again

Nitrates 10ppm
Nitrites 0
Ammonia 0 (I bought the api master kit yesterday to be sure as my strips weren't giving clearing readings)
Ph 7.5
Temp 25.7

This morning I've woken up to 2 dead harlequin rasboras!

Can anyone help with what this could be??

I'm now extra worried about my missing albino bristlenose

 

Morning guys!

I'm losing my fish like crazy!

Yesterday I woke up to 2 dead neon tetras. All my parameters were OK but I done a big water change anyway, added stress coat and everything seemed fine. The remaining 3 neons were showing no sign of illness, swimming as normal, eating but I lost 2 more of them throughout the day. Checked my parameters again

Nitrates 10ppm
Nitrites 0
Ammonia 0 (I bought the api master kit yesterday to be sure as my strips weren't giving clearing readings)
Ph 7.5
Temp 25.7

This morning I've woken up to 2 dead harlequin rasboras!

Can anyone help with what this could be??

I'm now extra worried about my missing albino bristlenose

Answer all of these questions in the link please. It will be very helpful.

Fish Emergency Template | 376562 | Freshwater Fish Disease and Fish Health

 

Tank

What is the water volume of the tank? Approx 170
How long has the tank been running? Was cycling a 100L for 6 weeks, then transferred this water over to this tank, with filter and topped up. Cycled for another week.
Does it have a filter? Yes, sponge and interpet p4
Does it have a heater? Yes
What is the water temperature? 25.8
What is the entire stocking of this tank? (Please list all fish and inverts.)
1 neon tetra
4 harlequin rasboras
5 endlers
4 guppys
6 panda corys
5 pygmy Cory's
1 (or 2) albino bristlenose
Cherry shrimp about 20

Maintenance
How often do you change the water? Once a week
How much of the water do you change? 20%
What do you use to treat your water? Stress coat +
Do you vacuum the substrate or just the water? Substrate and water

*Parameters - Very Important
Did you cycle your tank before adding fish? Yes
What do you use to test the water? Api master kit
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Ammonia: 0
Nitrite: 0
Nitrate: 10ppm
pH: 7.5

Feeding
How often do you feed your fish? Once a day
How much do you feed your fish? 2 pinches of slow sinking pellets and 1 alagae wafer
What brand of food do you feed your fish? Api and fish science
Do you feed frozen or freeze-dried foods? Frozen bloodworm a couple times a week

Illness & Symptoms
How long have you had this fish? 3 months
How long ago did you first notice these symptoms? No symptoms just dying suddenly
In a few words, can you explain the symptoms?
Have you started any treatment for the illness? No
Was your fish physically ill or injured upon purchase? No
How has its behavior and appearance changed, if at all? Nothing at all.

 

How often do you test water? A fluctuation in params can really stress fish out sometimes.

 

I had been testing daily. I posted my readings on this forum the night before they died because I couldn't make out the ammonia test but bought a master kit the next day and ammonia was 0

 

Have you been using prime or a dechlorinator. And did you monitor and do water changes during cycle

 

I used a dechlorinator yes. Also fluval biofilter. I did do a few small water changes during the cycle, maybe once a week. and monitored every week also.