Suggestions and Advice Needed! :)

[swimaquariumswim]

I have a 20 gallon L planted aquarium. I have a filter, heater and an air pump with an air stone which I just installed.

GUPPIES:

- 8 adult guppys (these are very thin and tiny, not like normal guppies, they are even thinner than pencils)
- 8 - 10 (not sure) baby guppies (all of them are from the same type of guppy above)
- 2 baby guppys (these are different from all my other guppies, I recently got them from the store. They are bigger than the other type)
- 1 male guppy (same type as I just stated above, bigger than the other guppy.

OTHER FISH:

- 2 neon tetra
- 2 glofish pink danios
- 2 zebra danios
- 2 orange swordtails
- 1 Albino Cory
- 1 Gray Cory (I don't know their name)
- 6 ghost shrimp

I know, that many of you will say that it is overstocked. I partially agree, but the 8 adult guppies are very small and look really small in the 20 gallon aquarium. The fish don't look crowded. There is still a lot of swimming space for them and I have provided many hiding spots using the plants (real).

keep in mind, I recently changed their aquarium and put them in this 20 gallon L, they used to be in a 15 gallon. They have been happy for 3 weeks and haven't shown any bad signs.

But:
1) 3 guppies just died today (2 of them been here for 2 years) (1 is like in between the baby and adult stage)
2) one of my zebra danios (I suppose its a female cause it's fat) is chasing the other guppies.

I am thinking of returning that zebra danio but she's never been like this. For the 3 months I've had her, she's been very peaceful.

So any suggestions would be good! And what do you think I should I do? I am doing 30% water changes every Saturday.

Thanks in advance! God bless.

[Urban Aquaria]

Your stocking ratio looks okay for the tank size (assuming your filtration is sufficient and the water parameters are safe and stable).

3 guppies dying could just be due to stress of tank transfer, anyways 2 of them have been kept for 2 years so they could just have died of old age too.

Btw, if your "guppies" are thin and tiny, they may not be guppies and could be endlers instead. A photo of them would help in their identification.

I guess your only concern is the danio chasing the other guppies, it could be a form of territorial dispute or display of "rank" in a community tank (could also be in breeding/spawning mood), this sometimes happens when a tank environment changes (like when you shifted them from an old tank to a new tank), they need to re-establish their respective pecking orders. Maybe observe them for a while more and see if they settle into a more peaceful state. If the danio still continues chasing the other fishes and causing problems, then you may need to consider transferring it to another tank or giving it away.