fish bullying

Question
Hi. I have a tank that is 105 liters and I have a red tailed black shark, discus, two clown loaches and a siamese fighting fish in it. I am having problems with the red tailed black shark and he is bullying my discus and has recently ripped his fins and tail.
The RTBS is full grown and about 4 or 5 years old and the discus is about 8 cm long and maybe about a 9 months.
I don't know what to do as I have a smaller tank (60L0 and there is a small discus in there. My bigger discus in the other tank was with the smaller one but bullied the smaller one until he just didn't come out. We moved the bigger discus away and the smaller discus is very happy and seams to be the head of the tank. The larger one is unhappy without the smaller one and spends his whole time being cautious and stressed, which isn't his normal personality at all!
Please help!!!  

Answer
aj,

To start off your tank is too small for the shark. He needs a minimum of 50 gallons just for him. Since it is too small bullying is going to happen. Do you have a lot of plants in the tank? You need safe havens for the smaller fish. I would remove the shark and put him in a bigger tank. If the big Discus is also bullying, then it is best to keep the smaller one in the other tank until he is big enough to fend for himself. I would watch the shark with the Betta if you decide to keep them in the same tank. The flowing fins and tail might make him a target. Good luck with all your fish.