Anyone familiar with large silver sharks

[mort]

Hi, my dad rescued this silver shark from his friend that had it in a tiny tank about 20 odd years ago. I've looked after it since then and it's grown to about 12" but for the first time I spotted it had an elongated anal fin. I can't find any pictures of other Bala sharks with the same fin growth, so puzzled if it's normal or a rarer morph.
It's hard to take pictures as it's a really low light tank and the clown loaches photo bomb everything, plus the shark keeps to the unlit areas or stays out of the way.

So here are some terrible pics that make it hard to see.

It's hard to see it here but it stretches nearly all the way to the clowns dorsal.

 

[alto]

Bala sharks do have quite extended anal fins, this guy may be on the longer side but as you say it’s difficult to see in the photos - he’s certainly lived a good long while with you

Tank details?

 

[Tim Harrison]

I've seen fins elongate in older fish of other species, so it might just be an age related thing.

 

[mort]

Bala sharks do have quite extended anal fins, this guy may be on the longer side but as you say it’s difficult to see in the photos - he’s certainly lived a good long while with you

Tank details?

It's about 2" longer than any other picture of big bala's I can find online.

The tank is 7x2x2, not really big enough I know but it's full of fish that are all 20-25 years plus apart from two blue firemouths. Its a tank I haven't done much with for the past few years tbh because in all honesty I don't want it but inherited the responsibility of looking after everything, it needs proper scaping and a new light (it's an arcadia strip led that has half of the leds blown but the fish really love it) but the fish are healthy and seemingly happy. It's hard to keep motivation when I can't add plants because of the fish and it takes quite an expense to change the hardscape so it's been wood only for a very long time.