What plants and gravel should I use for my 20-gallon freshwater tank?

When used as instructed, plant nutrients and fertilizers designed specifically for aquarium plants will not harm aquarium fish. Allow new aquarium plants to settle and establish themselves before adding any fertilizers. Use aquarium plant substrates such as CaribSea Eco-Complete Plant Substrate http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=9087 to get your plants established faster. Seachem Flourish Advance Natural Phytohormone Supplement http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=33890 will help stimulate root growth vital for overall plants health. Even though you have plants with low to moderate light requirements, be sure to use aquarium light specifically designed for planted aquarium use (sometimes called plant lights) and have the lights on between 10 and 12 hours a day. You may need to adjust the photoperiod (the amount of time the light is on) depending on how your plants are doing and to prevent unwanted nuisance algae growth.

Java Moss, Java Fern, Anubias and Amazon Swords are among the easiest live plants to care for and cultivate in an aquarium. You can use aquarium soil or aquarium sand depending on the species of plant(s) chosen. When medicating fish, it is best to remove them to a hospital or quarantine tank. This will spare live plants as well as beneficial bacterial populations, especially if an antibiotic is used. Medicated food is also an option.

A fish tank will need a filter, a light/hood and a heater. Make sure the filter is rated for at least twice the tank volume. The heater should be adjustable since water temperature will depend on the species of fish. Good "starter" fish include Tetras, Mollies, Danios or Tetras. A new tank should be set up and left running empty for several weeks before adding fish. A pinch of flake food can be sprinkled in daily. This "cycling" will allow a population of beneficial bacteria to colonize the tank and filter. These bacteria will break down wastes (ammonia, nitrites and nitrates) which are toxic to fish.

That's terrific news! It is great to read of your frog's recovery. Most keepers will keep a bare bottom tank. This will prevent ingestion of substrate and makes finding food easier for the frogs. It also makes it easier to keep the tank clean. Sand would be fine. If they inadvertently ingest some, it should pass easily. If you decide on gravel or river rock, make sure it it large enough to prevent ingestion.

Thanks for reaching out about your tank. Long plastic plants that extend from the bottom, all the way to the top can providing hiding spaces to decrease any territoriality or aggression. Live plants might be susceptible to the snails, depending on their type. Good luck.

An easily remembered rule of thumb is to plan on one pound of substrate per gallon to make a 1 inch bed. Using this formula, a 3 inch bed in a 55 gallon tank would need approximately 165 pounds of substrate. It is always recommended to get extra to have on hand in case you need it for future use. If you can clarify what is meant by "never used abstract can u buy now and use late?" in a new post, that portion can then be addressed.

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!