Painful Loss - 3 arowanas

[kuay5]

Lost 3 arowanas and a colony of cichlids yesterday. heart pain

1 x 21-22 inch Swift XB
1 x 10inch DFI royal blue XB
1 x 19inch Rainbow RTG

5 x pinestrip demba cichlids.

All because of my silly mistake. Went shopping for fish food and saw this product petfran clear plus. Read the label, it binds phosphates and clears water. So decided to try it, since i have not changed water for 2 weeks (2 largest arowana seems to be pairing with grunting sound made recently, so decided not to disturb them).

After dosing all is normal, so went out for dinner. When i came up, all arowanas breathing heavily, and hanging around on top of water. Swift XB started to lose control when swimming, banging into tank wall. Immediately changed 30% water and increased aeration as it looks like problem with aeration. Too late, swift XB flipped and died. 1 hour later, RTG flipped as well. In my sump, the cichlids flipped as well. After water change and increased aeration decided to leave the fishes alone.

This morning, found my DFI royal blue dead as well, it didnt last the night.

Most probable cause of tank crash - The rapid binding of phosphates, etc caused the sudden increase of organic waste, depleting the water of oxygen.

Strange thing is the arowanas and cichlids are affected, but the other tankmates like IT/AT, Discus and hampala barb seems unaffected.

Now i am just left with 2 arowanas in the tank. Only consolation is that my 24inch sumo RTG survived this crash.