Sushiray is right. I'd get the API liquid drops and put the test strips aside. Compare the results to see which is more accurate. Please do post the results if you get the API liquid drops.
Which light do you switch on and off? The room light or the aquarium light? I am not sure if you are aware of this but most fish do get skittish and can freak out thus injuring themselves when the aquarium light is switched on first. If I were you, I'd switch the room light on first as the gradual process will allow your fish to adjust to the lighting conditions.
As for the gash, this is tricky as it is near the eye. If it were the body area, I would have applied iodine solution on the wound to allow his wounds to heal quickly and prevent being infected by bacterial or fungal infections. What you can do here is change your water on a daily basis until the wounds heal. Normally, fish kept in very clean water will recover very quickly.
What do you feed him? You could add garlic to persuade him to eat. How does his poop look at the moment? You might want to check your pleco's poop and eating habits as well in case they may have internal parasites. A lot of fish that have white stringy poop and then loss of appetite harbor internal parasites which need to be treated immediately. If his poop is white and stringy, you could resort to praziquantel treatment. Praziquantel is a very mild treatment and does not harm your beneficial bacteria responsible for the nitrogen cycle but it can be lethal to a wide range of parasites particularly the common fluke infestations so that is a bonus since flukes are a pain to eradicate as well.
Which light do you switch on and off? The room light or the aquarium light? I am not sure if you are aware of this but most fish do get skittish and can freak out thus injuring themselves when the aquarium light is switched on first. If I were you, I'd switch the room light on first as the gradual process will allow your fish to adjust to the lighting conditions.
As for the gash, this is tricky as it is near the eye. If it were the body area, I would have applied iodine solution on the wound to allow his wounds to heal quickly and prevent being infected by bacterial or fungal infections. What you can do here is change your water on a daily basis until the wounds heal. Normally, fish kept in very clean water will recover very quickly.
What do you feed him? You could add garlic to persuade him to eat. How does his poop look at the moment? You might want to check your pleco's poop and eating habits as well in case they may have internal parasites. A lot of fish that have white stringy poop and then loss of appetite harbor internal parasites which need to be treated immediately. If his poop is white and stringy, you could resort to praziquantel treatment. Praziquantel is a very mild treatment and does not harm your beneficial bacteria responsible for the nitrogen cycle but it can be lethal to a wide range of parasites particularly the common fluke infestations so that is a bonus since flukes are a pain to eradicate as well.
