How to safely bring koi indoors for winter? Tank size, feeding, water.

Koi fry can be fed daphnia, brine shrimp (live or freeze dried), krill or hard boiled eggs ( remove the yolk, blend, mix with water and pour into the tank). Feed them multiple times a day. Once they grow some, you can switch to "fry powder". This is basically finely ground koi pellets.

Confirm it is made from a non toxic compound, such as polyethylene. Do not overstock it with fish. Provide adequate filtration and monitor water chemistry regularly. New ponds, just like new tanks, need to be properly cycled before fish are added.

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.

Without anything to use for scale, it is hard for me to tell how big your tank is, but in general it seems very small. Also, the water that is in the tank appears very cloudy right now, so that would be the first place to start. Water quality is very important, and will make or break your ability to house and care for fish. I would recommend getting a good filter system (you can visit a local pet store to assist you with brands in your area, as I am not familiar with what you can get in India). Be sure to bring the measurements (height, length, width) of your tank, or the gallons or liters so they can tell you what capacity of filter you will need. Everything else will depend on what types of fish you get - if you plan on getting multiple fish, they will need to be small - a general rule of thumb is one square inch of fish per gallon of water. Depending on the species you get, you may need to also get a bubbler to ensure there is enough oxygen in the water for them, and you will also likely need to get some sort of substrate for the bottom and cage furniture (different species have different air requirements, and some are secretive and like to hide). You may also need a water heater, depending on the species you would like to house. But, depending on how small your tank is, it may be hard to get a water heater that will fit. The food type will also depend on what species you get, as there can be differences in diet type between species. I hope that gives you a place to start, and good luck!

It sounds like you need to take a trip to your local pet store. The clerks there can help you pick out an appropriately size tank with proper filtration and heating that can help keep Sushi healthy. They can also let you know what water treatments you'll need for the water in your area, as well as test any water you bring it to see if it is OK for Sushi to live in. Pet stores will also carry commercial goldfish food which is a balanced diet that is given to them. It should have feeding instructions on it so you know how much is appropriate to give to Sushi.

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.

A 5 gallon tank is insufficient for goldfish. They produce a larger than normal bio-load (wastes) that can quickly overwhelm a small tank. Ideally, one goldfish should be in a 20 gallon tank with an extra 10 gallons added per additional goldfish. The filter should be rated for at least twice the volume of the tank. They are likely succumbing to ammonia and/or nitrite toxicity. If you test the water, it is likely both parameters will be dangerously high. Perform a 50% water change. Use only conditioned water that is temperature matched to prevent further stress or shock. Goldfish are cold water fish and do best between 65 F and 72 F. Plain aquarium salt, NOT table or Epsom salt, can be used to reduce stress, improve gill function and aid in recovery. Dissolve 1 teaspoon per gallon in a cup or two of tank water and gently pour it into the tank. Treat for no more than 14 days then perform a partial water change to decrease salinity. A 5 gallon tank would be appropriate for one male Betta or a small school of Neons (3-5).