Can any one help my iguana?

i bought my iguana for my boyfriends birthday in april so hes about 4 months old and his name is jack. he eats everyday, he is super green and to me he seems very happy. he has a really big tank and he sheds his skin like every other week. today i changed his water and found like six or seven bugs in there three of the bugs looked like little tiny ant flies but i dont know if thats what they were they were the size of ants with wings on them. but thats not my concern, my concern is the other 3 or 4 bugs they were reddish and had like 4 to 6 legs they were bigger then fleas but smalled then ticks i didnt see any on jack but im scared that his tank is filled with them. in his tank i have about 4 big sticks from outside so maybe they come from that. does any one know what the reddish bugs are and how do i get rid of them? and is jack in danger from the bugs ? do i have to throw away the sticks or can i clean them? i also have a cat who goes outside do you think he brought them in but after i seen the bugs in jacks water i checked my cat and didnt see any bugs. please help my iguana