Woo!! Maybe I could make some of there for my big cichlids ^_^ thats really cool.
do you notice different types of fish use the bridges more then others etc? would be amazing to watch different fish interact with the bridges.
Yes and no. Some of fish of the same species are comfortable using them, while others aren't. Some fish will only use them at night, when the lights are off. I've painted the outside of the bridges, except for in the front, so that less light shines in them. Still some of the fish get claustrophobic or freaked out from the reflections of the acrylic, so perhaps I'll need to paint the inside also.
A few tidbits:
I've heard stories from others that some territorial/aggressive fish may troll the bridges to keep others from passing.
I once had a fish jump through an empty bridge into an empty tank. So you need to be careful, and be sure to remove an empty bridge, if you are doing maintenance/breaking down an adjoining tank.
Small bridges that larger fish can't enter, can be used to connect refugium tanks for fry, juvi's, feeder fish, snails, shrimp, ect. When the refugium gets over-populated, some will leave that tank, and get eaten by the other fish.
Custom tank stands may need to be built so that the water height is the same in the aquariums.
