One of my Angels died

Would this be from Ammonia?

It wasn't looking healthy yesterday but I thought it might improve, today its dead....I seemed to have red around its lips and eye.

My tank isn't very old so i don't think its cycled, yet the other angel looks fine.

I don't have a test kit due to lack of funds, but I've been doing 20% water changes every 2 days.

Its a 55 Gallon tank, UG Filter and a Sponge Filter(does bio and mechanical), its at 26 Degrees Celcius atm, and its been running for almost a month.

I have a PH kit and its 7 so nuetral.

I will buy an ammonia and nitrite kit next week hopefully. I just got a new fulltime job so I am planning on buying a canistor filter and better lighting.