New To The Hobby: Danios Acting Odd

[grant_folley]

Hi, I am new to the forum and new to fish keeping. I have been gifted an aquarium by a friend, who has helped me to set up my tank, using the previously established filter. After a couple of weeks and a set of water results (PH 8, Amonia 0, Nitrite 0, Nitrate 5) I introduced 5 Danios (2 Zebra, 2 Leopard, 2 Pearl) unfortunatley I lost one of the Zebras on the first night. However after another week of stable water test results I introduced 8 Neon Tetra and 4 Peppered Corys. Again unfortunatley I lost two of the Tetras and one of the Corys over the first day. Following another week of stable water results I introduced a baby Bristlenose Plec, 4 Algae Shrimps and a couple of snails.

All has been well in the tank for almost a week, with water results as previously stated. However over the last couple of days one of my Danios (leopard) is looking unwell. It is not eating, staying at the bottom of the tank and for the last day has been swimming eratically and flicking it's body. There are no external signs of diesease on thie fish. All other fish are acting normally.... what should I do? Could the problems spread to other fish?

Also, as described above I have lost some fish, when I have introduced them into my tank. Am I doing something wrong, what should I be doing when I intoduce new fish to the tank?

Any advice would be appreciated!
Thanks

 

[Marve99]

What are you using to test your water stats?
What size tank do you have?

What technique do you use to acclimatise the fish?

Adding 8 neon +4 cory was a big increase in stock which could have resulted in a spike as the filter may not have been able to cope.

Neon like a mature tank also, they don't do well in new set ups

 

[WILDER]

Neons really need mature tanks of 6 months.
How many gallons is the tank.
How long did you climatise the new fish for.


What are your latest water stats.
Any excess mucas on the fish body or gills.
What do the gills look like. Do they look pale with excess slime or red and inflamed.
Any red pin prick marks on the fish.
Any signs of laboured breathing.