thank you for the suggestions.. @Fresh2o, @Reygan2, @dcutl002
when i started, i had 6 pairs of different fishes. i was not aware of the cycle concept and never tried to google it seriously. simply went to the pet store and he suggested the tank of 6 gallon, sobo wp1200f water purifier, some gravel of white marble stone of quarter to half inch size some coloured pabble stones and a submersable blue light.. he gave 2 fake ornamental plants and an ornament (broken ship) and i purchased 2 live plants . all costed some around 1500 INR.i.e., 25 USD..
all the fishes which he gave were sacrificed to the nitro cycle. (pet store person did not mentioned about the cycle and the overcrowded ) i then got to know that the zebra danios are the hardest for the cycle.. i tried. they successfully survived.. when i bought they all were not more than a quarter inch in size. i bought 14 of them.. the vendor told me that those were the danios... i doubted because the danios have horizontal lines all over the body but the fishes what i have have the yellow belly and they are really active..
the gravel which was given by the pet store vendor was changing its colour and i was doing only 50% water change every month..i had 2 live plants for good oxygen supply in the aquarium as i did not bought the defuser.
i viewed some youtube videos of sand substrate coz i was concerned about the live plants. the roots were comming out and the fishes were biting it..i wanted to purchase some substrate from the pet store vendor as well as from amazon but it was above my budget. so finally for some sand from a construction site. here we dont have pool sand and play sand...the sand which i have used is of river bank.. the pebble stones are used to hold the plants in the sand. you may be right aabout the overcrowded but it looks good for me.. i thought of adding 5 more pairs of the same...(dropped the plan)
for the time period and having this tank, i am planning for a 100g acrylic tank by the year end. i have some plan for that.. it should be full of live plants(aqua scaping) few cleaning fishes and big school of neon tetras.
yes, the light is blue and i hate it.. i will try to make a white led
light for them in a short period of time..
thanks and regards