Update, my bad , pardon an oldman , those tree bark is sold by gram , 100gram for RM8 , i touched it, feel real but i'm not expert.
picture enclosed , each of those pack is like 400g , so 4 x RM8 = RM32 each.

Size is like 60cm height x 30cm ft width


And those cheap mangrove wood & stone on shelf, price range RM3 till RM30(big chunk) , i use those in my crayfish/vampire crab tank, so far so good.
Just need to boil and let it settle in a bucket for few days to leech out tannins.

Nilufar Pet & Aquatic inside Tesco Jalan Kuchai Lama.

This shop is on the second floor of Tesco , around 10k sq. Got Pet hotel(boarding, day care) beside selling aquatic plants , fish , newt , frog , scorpion
etc. Their are giving free membership for purchase of RM10 for first 3000 customer. Discount is 5%.