I have a 10g tank that was bought as a result of my grandmother buying my daughter a goldfish in a very tiny bowl for her birthday without my ok. I was upset, but invested the money to buy a better tank. I understand that 10g is not enough for a goldfish, but seeing as how it was only .5 inch long at the time, I figured I could pull it off for 2 weeks till I got my next paycheck. Long story short, the goldfish died.
My daughter really wanted fish after this, so I bought a heater, cycled the tank and bought 2 male guppies and 5 females. Along with these... I bought 4 ghost shrimp and 1 apple snail.
The snail and shrimp have thrived, but all but one male guppy has died. I have tried introducing both males and females to the tank since, but he harasses them all so much and within a week they die! My guppy is gorgeous and healthy in appearance and attitude (other than being aggressive).
Three weeks ago, I added 7 cardinal tetras. So far he is not having any issues at all with them and they too seem healthy and thriving.
Both my daughter and I are in love with this guppy and do not want to risk losing him. Heck, he even takes frozen brine shrimp treats out of our hands! We have had him for about 8 months now, so he is considerably larger than most I can find at stores and I feel guilty with losing so many already just to lose them due to him being mean.
There are tons of hiding spots on all levels of the tank, so I do not feel that cover is an issue. My real question is this: Should I keep him alone in the tank and keep it as is now, or should I still try to introduce a few females to the tank again? I know that fry will be an issue that will occur with females, but I am prepared for that with someone willing to take them all and many extra tanks laying around ready to be set up.