Why are my fish dying? (First tank)

[seabear]

Just started my first planted tank this year, so I'm new to pretty much everything.
A few of my fish (and shrimp) have died within the past month or so and I was hoping to get some insight. I feel like it might be a compatibility issue or possibly the Ich.

I have a 20gallon long tank, freshwater, Aquaclear 50 filter,
planted with 2 -13watt CFL's and 2 - 13watt CFL blacklights.
The tank was fully cycled (fishless) for a little over a month before I added my fish.

3 Cardinal Tetras
3 white skirt blushing tetras
1 black molly
1 neon guarami
2 male fancy guppies
2 female guppies
2 harlequin rasboras
2 cory catfish
2 japonica shrimp
3 cherry shrimp

2 of the cherry shrimp died pretty quick... not sure how.
then last week one of the guppies died.
2 days ago another guppy died
and today 1 of my cardinal tetras died.

I've noticed there's one white skirt tetra that seems to bully the other tetras around nipping tails... so he is one suspect.
Also semi-recently I noticed little yellow spots on my cardinal tetras... like a sprinkle of yellow salt on their body. Didn't think much of it until one died. Could it be ich?
If so... how could I treat/prevent it on the others?

Also I'm open to hearing advice on the selection of fish I have any maybe which ones shouldn't be housed together.

Thanks!

 

[Coursair]

Schooling fish need schools.
Skirt Tetras are nippy and can be nasty, esp if you don't have enough.

Social fish should be in groups of 6 or more. Having a mishmash of this and that doesn't work well usually.

I would take Skirt Tetras out. Add more of the other types, once tank is healthy. You'll need more cover before adding more Cherry Shrimp.


Test your water. Post results.

How often are you changing water ?
What temp is tank ?


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[seabear]

Thank you, that makes sense.
Ya, I forgot to mention that I tested the water as well... ammonia and nitrites are at 0 .
and the temp is around 82F.
I have been doing 10% water change once every so often (every couple weeks maybe).
Should probably do another one soon though if there's sick fish in there..

 

[abbyn]

If you are doing a ten percent water change you should probably be doing it every week. Some people will do 25% every other week. Make sure you are being thorough when you clean your gravel. Water quality can get bad quickly especially in a smaller tank and when you have lots of fish.


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[Coursair]

If you have ill fish I'd be doing 25-50% PWCs every week.

Are you testing with strips or liquid test kit ?

How long ago did you set up the tank ? Have you added any new fish ?

82f is ok for Cardinals but high for some of the fish. Less oxygen in warmer water.

There is a list of questions Stickied to the top of the unhealthy fish forum, answering all those questions will help you get better answers.

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[seabear]

Yes, sorry I did not see that sticky until now. Here's what I got:

The tank was set up around Jan 7 2015 and cycled for a little over 4 weeks before I added fish the first time. after that, I added the 3 cardinal tetras and 1 more white skirt tetra as well as the shrimp (this was a couple weeks ago).

I have not vacuumed the gravel... I guess I was under the impression that the bacteria necessary for the cycling process live also in the gravel and that vacuuming it should be very minimal. But I guess that is not the case when I have fish already present?

I acclimated the fish by first floating the bag, then by adding small amounts of tank water over 20-30 minute periods before netting them out into the tank (not dumping bag water).
I have been using the liquid API testing kit.

No new decor or substances have been added since the fish have been present.
The last fish were added probably 2 weeks ago... maybe more.

And I have been feeding tropical fish flakes


If the temp is a little high, how would I go about lowering it?

 

[stooker]

I recommend much more and frequent WC. 50%+ weekly. Your parameters look good, but WCs do more than just reduce nitrates.

 

[Mebbid]

What are your nitrates at? A 10% change every once in a while is not nearly enough for a tank stocked with that many fish.