if u have enough places for the bichir to hide with the pair it should be fine........ u just need to watch them......... u can put any fish in the same tank and for awhile it will work....... ive had a 240 amazon type tank with oscars blue acaras gts and some pimelodus ornatus i droped in about 300 neons and the fish that where in the already brought the number down to about 100 after like a month but then they went down to 50 in the next 2 months then the 50 lasted about a year then i put six 5" red tail barracudas and the rest where gone in like 1 week or 2.......neons where ment for feeders this tank was pretty planted and all fish where raised it the fully planted tank except barracudas and neons...... i say if u get all the fish when they are small they should be fine........