That sure looks like an awful lot of fan to be blowing dry air directly into your vivarium. Please be careful. It is extremely easy to dry things out too much, killing plants and frogs. Most vivarium fans seen here on dendroboard are being used passively. They simply move air around inside the viv. Then they will also incorporate passive screen vents.
Some people blowing air directly into their vivs do so for only very short periods of time, after a misting cycle.
In any case don't forget to screen it off. Your frogs will explore every inch of your viv. Make sure they cannot explore that inch.
Please, please, please, oh please sand those edges! Those curved cuts are razor sharp and it's only a matter of time. Get some heavy leather gloves, fold up an old rag, wrap some 100 or 200(ish) sandpaper around the rag, and carefully sand away. Sanding glass will wear out your sandpaper very quickly, so get a few pieces.
Here is quick, simple, elegant, and very strong solution for you. A large marble, with a generous dollop of silicone to attach it (after cleaning with rubbing alcohol). Silicone was strong enough to glue that tank together. It will be strong enough for your marble handle. Another solution I have used is a decorative polished rock for a handle. Use the same silicone.
Now fess up. Your first time cutting glass and you pulled off a curved cut? You are talking to a glazier of over 20 years... You still sticking by that story? It wasn't perhaps an accident you are trying to take advantage of? Come on...
(If you really did, Kudos to you!)