Are Corys Aggressive?

[symon_say]

Hi

I have 8 glofish in my tank doing just fine, a few days ago i introduce 6 bronze cory to the aquarium and yesterday one of my glofish died, and today another one did. All this after corys are in, i have read all over that corys are peaceful fish. Glofish are still small the bigger one might 1 inch and the corys are bigger the smaller one is like 1.5-2 inches.

Water parameter are all fine, ammonia and nitrite 0, nitrate 10ppm, ph 8.2, tank is a 55 gallons with only the corys, the glofish and 6 guppies i'll introduce in a few minutes.

 

[Katty]

They are absolutely peaceful, I don't think they even have the physical ability to hurt anything. They might have introduced a disease though.

 

[symon_say]

What should i do in this case, cause i'm completly new to this.

 

[mbsqw1d]

I can guarantee that your Corys did not attack and kill your glo-fish.

The possibilities are:

Your tank hasn't completely cycled and your filter does not yet have enough bacteria to handle the sudden influx of fish and your ammonia has 'spiked'​

Your corys have brought a disease/parasite/infection/bacteria along with them from the shop that has adversely affected your glo-fish​

coincidence! Your glo-fish may have been on their way out for some other reason anyway​

your glo-fish have died from shock at how cute the corys are (sorry)​

I would start doing 30% water changes every other day for a week to ensure you're not having problems with high ammonia and nitrite.

Otherwise, how long has your tank been setup and did you 'cycle' it? What filter do you have? How often do you clean/maintain/change the water of your tank?

 

[symon_say]

Tank is cycled for about 3 weeks, i have 2 filters, aqueon 55 and aquaclear 70, ammonia and nitrite were 0.00 yesterday, today it spikes between 0.25 and 0.50, i change about 15 gallons from my 55 gallon tank every week.

 

[mbsqw1d]

i honestly think an ammonia spike killed the glofish... adding 6 fish at once must have been too much for the bacteria in your filters to handle. The bacteria within a filter will only grow depending on the amount of ammonia and nitrite (food) available in the water. Your filters may have cycled sufficiently for the glo-fish but then the addition of 6 fish meant it had to cycle more to meet your demands.

 

[Harlequins]

I agree its due to adding the corys you have got the spike,do a good 50% waterchange to get rid of the ammonia/nitrite ,then test again if its still up then do another w/c.

The filter will catch up eventually but feed minimal and do w/c if necessary.

Did you do a full fishless cycle with ammonia? - if that cycled 3 weeks ago and its just had the glofish in there,then the bacteria would have died back by then enough to handle just the glofish,hence now putting the corys in has knocked it a bit.

Testing & W/c are your best friend,test several times a day and keep the stats near zero and you should be fine.

BTW corys are not aggressive

 

[symon_say]

Ok, i'll do that, i'll do another water change and see how much it spikes, my problem right now is that i have to leave for the weekend, and can't take care of the tank, i'll see if i can re-house the cory until i'm out.

 

[guppy love]

your glo-fish have died from shock at how cute the corys are (sorry)​

(sorry too!)

I call mine my underwater kittens!

Good luck with the rest of your fish OP.

 

[symon_say]

Everything is under control now, the ammonia spike was the cause of all my problems, thanks a lot for the help.

 

[Rynofasho]

Glad it all worked out!