Help . . . I have an all-corydoras 20 g long planted tank, large-grained sand substrate, cycled w/ proper readings for 5 weeks before adding fish, pH 6.7, 77 degrees, ammonia and nitrAte both O, nitrIte had a mini-spike of less than 1ppm for 2 days but got rid of w/ 30% water change. The water here is very soft.
6 small (1" - 1.5" long )corys were the first occupants, introduced 10 days ago, so the whole tank is technically under quarantine (no other fish to be stocked for 2 more weeks).
Among the 6 are two C. agazisii (yes, one of the confusingly similar spotted ones). Only these two are pale and acting strangely.
On one of them, the black spots seem to fade away on and off to a pale yellow background color. At times he seems almost alll yellow. On the second one, the spots are more visible more of the time.
While they both come out to eat and forage, they stay hidden and sedentary MUCH more often than their tankmates (a C. caudipunctatus, 2 c. aeneus "laser" types" and a C. loxozonus). All the others seem normal.
I am currently in the 5th day of a 5-day Maracide treatment for suspected velvet (the old concentrated version of Maracide w/ Tris/Aniline green).
Can you please add your location to your profile, thanks.
Cory's very often go pale, it is usually a reflection of their mood and I would be more worried if they were going dark. The colour of the substrate and environment can have a marked effect on colours as wel, with different species reacting differently to the same suroundings. If they are eating well and resonably active I don't think there is much wrong. Angain some species are more active than others and a different times of the day.
Thanks for the words of reassurance. As of today my C. agazissii are still eating and getting a bit more active, though compared to their tankmates in the shoal they're still fairly sedate.
Has anyone here had experience with Cory species that generally tend to be more timid and secretive than others?
Yes, my sand is pretty light-colored, which could explain some of the paleness.
