Silver Arrowana

[pisces]

Just wondering if anybody could solve this mystery for me. I've had my silver arrowana for about 6 months and it's now14 inches long (it was about 8 inches when I purchased it). When I first got it I had fed it live feeders but stopped due to the level of 'inhumanity'. I now feed it frozen tiger shrimp and have been for the past 4-5 months, and boasts a vibrant orange tinge on the scales. But this past month, I've noticed that there was what looked like a little sac on the bottom of the tank. The sac is white in color with a little tinge of pink and semi transparent. When I fetch it out with my net it stays intact but upon observing more closely I noticed that it encases what looks like little white uncooked rice. This has happened 3 times and and I'm very curious as to what it is. Any info what be greatly appreciated. Thanks!

 

[Calusa]

I've witnessed these sack like things (only red) from arrowannas at my LFS, however, I read somewhere they were egg sacks (forget if they're from their birth, or females with eggs, but everyone at the LFS had them, so I think it was the first option). And a few days later they were no logner there. But if yours is older, it wouldn't have an egg sack from it's birth, or hatching... maybe it's some weird defense/ frightened mechanism or response?

Maybe it's actually 'pooping' out it's stomach?