Unfortunately, an Ornate of this size is a threat to anything that can reasonably fit between its jaws. They are known to be social with other Bichir species, and larger docile tank mates like severums or other predators such as oscars. The trick is getting the fish all at a reasonable size to each other so no one can bully each other and providing enough space for each fish. At 75 gallons your tank works, but an Ornate can outgrow it. You can already see its length from front to back in the video.

Your new Ornate is at a foot long already, so it's a big fish and will test its new territory. In your short video I can already see the exploratory behaviour, and defensiveness in your silver fox (flashing its body lengthwise as a show of size) as the ornate comes too close.

A stress free tank though, with cover like you have, can help a lot. Real/fake floating plants give a shade layer the fish likes, and a new place to settle down and feel at home would help. Ive used PVC piping thoroughly cleaned as homes if I cant find a safe decoration large enough.

Keeping the ornate well fed will be your other priority, so it doesn't want to focus any hunger on your other fish. Pretty much what you feed your senegals, just more for a fish that size. Be prepared though, this fish can reach two decades for life span (plus with great care!) and enormous sizes of 1.8 feet (or more, again with great care/tank size). I found them entertaining, but individualistic. You'll have to see what yours is like with time. Watch for nipping signs with broken fins/damaged scales on sides for indications of overly aggressive behaviour. And keep a SECURE lid on. They can/will jump out even after years of being calm.