Aesthetically, you have a larger area of viewable rock to be mindful of. I don’t know what the back of my tank looks like, it could be an awkward mess, but it’s flush against the wall so it’s irrelevant. With a peninsula, you have three sides to try and zhuzh.
For me personally, peninsula tanks also offer a challenge of balancing fish hides. I’m a big believer in creating spaces where fish can hide from people looking in the tank, not just other fish. There is a natural tendency to go narrow with the rockwork in a peninsula tank, and you can end up compromising space for fish, almost like some of the NSA tanks that are kind of “in” at the moment.
And the flow issues are well documented as well. Not that it’s that hard, but throwing another power head on the open end of the peninsula mucks up the elegant look for sure.
None of these are insurmountable hurdles, they’re just considerations. A lot of the remedies to these problems with traditional tank layouts are tricks that don’t work with peninsulas so you have to get more creative.
The other layer of the onion is traffic around tanks. Peninsulas by nature jut out into rooms. Sometimes it feels natural, sometimes it’s awkward. Only you can really judge this aspect for your situation. If there are children in the house, maybe think extra hard about a big piece of furniture full of animals that cuts into a heavily trafficked area.
Based on your layout, I would personally put the tank in the red area directly across from the kitchen opening. The other red area seems a bit “tucked away” and the peninsula layout doesn’t have the charm of being viewable from multiple rooms, which is the biggest plus to the layout, imo. If the extra viewing area is just the hallway into the dining room, I don’t know if that’s worth the extra effort to set up and accommodate the tank. If it were split between a living and dining room for example, it might be worth it. But as it is, I’d go with the leftmost red area.
