Is my 90L fish tank big enough for my fish to be comfortable?

All these fish can grow quite large. The loach would be the "smallest" at about 6 to 8 inches when full grown. The Oscars can reach lengths of 18 inches and the Texas cichlid and sharks can reach a foot in length. All these fish will require much larger tanks than the ones you have now. The three Oscars alone would do best in a 125 gallon aquarium MINIMUM. The others may thrive in 55 to 75 gallon tanks. To leave them in small tanks will cause stress, aggression and likely infection.

Thanks for reaching out about Timothy and Lola. First suggestion is to get a large tank. The general rule of thumb is 1" of fish per 3 gallons of water. Test and correct water quality for pH, ammonia, nitrites and nitrates. The better the filtration, the higher the bio-load. So better filtration or a second filter could help. Good luck.

Thanks for using PetCoach. There really is no solution other than a bigger tank. 50 gallons is likely too small for 6 parrot fish once they reach full size. If you cannot get a larger tank asap, I would recommend setting up several smaller tanks, or returning or rehoming the fish until you have the correct set up, A good rule of thumb is 30 gallon for one and 10 more gallons for each additional Blood Parrot. As with any fish, the bigger the tank the better. Overcrowded they are going to fight and become stressed which can lead to disease and possible death. Here's a bit more info. http://www.parrotcichlids.com/parrot-cichlid-tank-setup.asp Good luck.

Thanks for reaching out about your fish fry and including photos of the tank. The tank size should be adequate but also depends on the number of fry being added. Proper filtration and oxygenation will be very important. Good luck.

Platys, Mollies, Neons, Dwarf Gouramis and Cory Cats are all excellent choices. Be sure to not overstock the tank and allow it to properly cycle before adding fish. You would need to contact the Petco in question and ask them directly. Some locations will accept fish to rehome if they have the tank space. Most local fish stores will not, due to risk of disease or parasite transmission.

The goldfish can get very big and may require a significantly larger tank as they grow and grow. As a rule of thumb, you need 1 gallon of water per inch of body length of fish. So if you have three 1 inch fish, you will need 3 gallons of water. I suspect you are at your max already in the smaller tank. Just so you know, most people do not have goldfish in tanks with tropical fish. You may consider getting two tanks One for your cold water fish like the goldfish, and one for your tropical fish that require a warm water temperature. For the goldfish I would suggest a minimum of a 20 gallon tank. For the Danio, I suggest to get a few more of these as they are schooling fish and a 10 gallon would be just fine. I hope this is helpful and please feel free to post any additional questions.

Thanks for your questions about your tank. You have a number of fish in your tank already - a general rule of thumb is 2.5 square centimeters of fish per 3.8 liters. Depending on how large your fish are, you may be close to the carrying capacity of your tank, and you will also need to plan on how the fish in your tank will grow over time (mostly the rainbow sharks). If you are looking for tank mates for discus, it is best to look for fish that are housed in the same temperature zone, and occupy different areas in the water column than they do. Examples would be bottom feeders like cory catfish, those that live on the sides and bottom such as plecos, and those that are in the middle of the water column like some species of tetras. For the question about vacation - I would not recommend leaving your tank for that long without someone checking on it regularly. Power outages can be detrimental for tanks, and water changes or additions would likely be required. Also, automatic feeders also have the potential to fail, and this could cause a large spike in ammonia if a large amount of food was fed, and starvation if there was no food dispensed over a long period. I hope that helps to answer your questions, and thanks for using Petco Pet Education Center, formerly Petcoach.