Hi guys,

I have a new 220 litre tank, been cycling without fishes for a month. It is a planted tank. I also have a small 20 litre tank in office with guppies and shrimp. This are the pictures of the 2 tanks.

Recently I added guppies to the new tank. Strange thing is, my guppies from the new tank have been dying 1 by 1 but for no apparent reason. These are fancy guppies with 3 panda guppies. 5 from C328 (Left with 2), 33 from Nanyang Aquarium (Left with 11), 15 from Neo Kim Suey (Left with 5). The 3 panda guppies are quite aggressive and have been chasing the other guppies so I removed them but guppies continued to die. Next, i thought CO2 was too high so I turned off the CO2 supply but they continued to die.

Parameters tested with API, PH:6.5 Nitrites:0 Ammonia:0 Nitrates:40. I also have carbon dioxide injection and the CO2 reader shows the levels are in acceptable conditions.

Is this because my tank has not been cycled? Will it be helpful if I cycle the tank using a sponge from my hang-on filter in my office?

Pictures: https://imgur.com/a/h6njJC2