Help.......Thread like worms !

[Prison Shepherd]

Help i have found a few red jelly like balls in one of my tanks today. When i got them out, they were moving! and went from a mass into a ball shape.....when put into water to view, they started to appear to open up and very fine white thread like worms came out? what are they.....I have had fish for 10 years + but have never seen this before.
Please help me as i was going to turn this tank into a 3 breeding tanks.