a little scare

I had a little scary incident during the weekend. My 50 gal barrel drum fish tank turned murky and there were signs the fishes gasping on the water surface. Admittedly, my sponge filters were not replaced for almost 3 weeks. Algae already accumulated along the inlet pipe. Secondly, i was a little bit overfeeding them partially due to the fact of trying to overcompensate from lack of filtration management.
2 more fatality on Saturday ,must be the females because they were almost half the size of other fish (50mm size after 2 months). Time for 50% water change instead of 20%. Having no significant rainfall the past week, i have to make do with house rooftop water tank. Scooped up sludge and clean up the submersible pump, almost choked with slimy grey matters and put up another finer screen lining to the sump gate.
Sponge filters were replaced finally and re jigged the siphon bell (it was choked with algae too) by putting another finer screen lining.
Its time to start looking for the 1000 liter IBC to transfer my teenage age fish. The barrel drum would be too crowded soon for them.