A few things...for a Freshwater tank

The first day, you are about to come home with a fish tank, you might have a picture of a colorful tank with fish swimming all around, eating food and listening to what you say. I wish I had known a few things before:

• Beginner's should ideally start with a 20+gallon tank. A smaller one works, only if you want to have 3 or 4 of them. 
• Thumb rule- size of full grown fish x number of fish = gallons required. 
• The filter size, should be on the higher side- for 20 gallon, you might go with the filter for 20-30gallon tank. This will help to balance ammonia and nitrite level in the tank. 
• For fish that lay eggs, like Tetras, be careful when you gravel vac the tank. You might scoop out some of the eggs and it will certainly cause stress, aggressive behavior. 
• Overfeeding is a common thing. Feed as much the fish eats in 3-5mins. 
• When you move decor around or introduce new fish, or clean make sure the aquarium light has been turned off. The heater as well, during cleaning and water change. 

Red wag platy

Red wag platy- 2.5", freshwater fish, live bearers.

Fig: 6.1

24th Feb: We introduced 3 of these in the tank (2 females, 1 male). They usually recommend 1:2 ratio. Look at the fin to differentiate between male and female. The male has its fin pointed, where as in the female it fans out. Water test indicated high level of nitrite. Adding aquarium salt (non iodized) prevents nitrite poisoning, reduces stress levels and could also treat certain diseases.

• 10% water change, replaced water in the tank and added aquarium salt.
• Placed red wag platy in the tank.
• Next day: one of them started itching itself against gravel and other decor items in the tank. It seemed as if it was suffering from Ick or Itch. A day later, another platy showed the same symptom.

We did 25% water change, added aquarium salt, removed carbon from the filter and put one ick tablet. It turned the water greenish blue for a while. I hope they all survive.

Adding another pair

Fig: 5.1

We added another pair of Tetra within the first few days. Since they are schooling fish, it is usually recommended in groups of five or six. The dynamics of the whole tank changed! They got along well with each other, there was less fin nipping. It seemed as if they were doing well.

A month later, we wanted to introduce another variety of fish - Platy.

We bought five (Sunburst wag Platy) and added it to our tank. They were amazing. Beautiful, colored.

Introducing new fish-

• Turn off the lights, Float the bag for about 15mins.
• Let the temperature of the  water in the bag and the tank equalize. 
• Using a net, transfer them into the tank, one by one. The new ones will try to look for hiding place as soon as they get in. The tetras were busy fin nipping. By next day morning we found most of the new ones had their dorsal fin nipped :(
• Three days later, we lost one platy and one tetra. 

The ammonia and nitrite levels increase. Fish undergoes stress, adjusting in its new home. At times bullied by the fish occupying the tank prior to its arrival. As a beginner we are so excited to add new fish, that we do not take into account the size of our tank. If you do the math right, 5 Tetras and 5 Platys would need a tank size 22.5 Gallon. A thumb rule, (size of the full grown fish) X (number of fish). 

Tetras usually grow up to 2" and Platys up to 2.5". 

We returned the platys and added one more tetra and left it at 5 tetras in the 15 Gallon tank.