Ive told this sotry a million times but Ill tell it again:
In me experience retics are far more sensitive then other rays...well at least motoros. I had a retic for about 3 or 4 months. He was perfectly healthy, fat, eating everyhting I gave him, even had a perfect tail. He was about 5" disk size. about a3 weeks before he died I bought a motoro. The motoro was his size but deathly skinny and severly beat up as she was housed with jack dempseys, clawed frogs, RTC ect. Well they were together for a few weeks and everything was fine adn th motoro was gaining back her strength and about this time summer is rolling around.
I do my usua ever 4th or 5th day 50% water change and when Im done for some odd reason I decide to test my water and Im shocked to see that I have a high (about 1ppm) ammonia reading. Now before anyone says anything my tank was well filtered and had been running for over a year and Ive never had problems before.
Not knowing why my tank had that reading I decided to test my tap and sure enough I had alot of ammonia coming out of my tap! The next morning my retic seemd sick and five days later died. The motoro on the othe hand who still was far from 100% was never phased and survived....