Suggestions For Additional Fish

[Crystal90]

I have a 40g tank which has 6 corys, 6 buenos aires tetras and 1 mystery snail. I would like to add a few colorful fish and I need some ideas on what species would work with these.
 
my water parameters are:
    temp     76-78
    ph         7.6-7.8
    ammonia    0
    nitrite         0
    nitrate     20-40
 
Thanks for your ideas.

 

[RyanTheFishGuy64]

platies...nuff said

 

[attibones]

What is your water hardness? Which Cory species have you got? What are the tank dimensions?

 

[N0body Of The Goat]

Hopefully you are letting that tank temp cool during a winter period, Buenos Aires Tetras are not "tropical" fish, they have evolved in a region where the temp drops to ~16C.
 
Taking the seasonal/temperate conditions above into consideration, temperate Corydoras should be chosen, such as Peppered Corydoras. Many common Corydoras spp. require ~21C as a minimum temp but the are exceptions (such as high end tropical C.Sterbai).
 
If your Corydoras and tetras are truely compatible, with the catfish being one species, then the real answer here is 4 more of each species... 10+ groups tend to behave far more natural and look far better than multiple "minimum 6 groups." 

 

[Crystal90]

Thanks for your suggestions. I have removed the heater because the tank was staying too warm (closer to 80). I guess I missed the fact that the BA tetras like cooler water. The corys are 2 pepper corys and 4 green corys. I guess the water temp they prefer is close to each other. I was concerned when the temp dropped to 72-74 during some cooler evenings but I guess I don't have to worry.
 
The tank dimensions are: 36" L / 15" W / 16" H.  I know we have hard water but I haven't tested for it. I've had most of the fish for over a year and a half and everyone seems active and healthy.  I just didn't want to overstock the tank.