a disaster about to happen knowing that the OP is only 13. The tank is definitely overstocked.
i'm not trying to troll but if i were you, i would return the rtc and tsn right away. They will grow big right away and outgrow the 90 in 3 monchs (rtc).
You can keep the other fish for about a year and return them.
Worst of all the rtc will eat the other slow tankmates because it grows the fastest. These fish are known to eat a tank mate 3/4 the size.
Anyways, it your choice. good luck. I'm 15 and I can relate to you