I don't think you'll be able to confirm the sex of your fish without venting. Sexual dimorphism is relatively weak in most Vieja. Only in older males will the head develop a hump, and at 5" your fish isn't old enough for that. Give it a couple of inches.
The faded colors likely indicate that your fish isn't comfortable in its tank yet. The substrate is very light and reflective, which may be contributing to the fish's washed-out appearance. It may also be reacting in a submissive manner to tank mates. Genetics also plays a role in colors, but it is impossible to say how that will play out.
Vieja will tolerate salt. The temperature range you have sounds fine, although it would be best if it remains relatively stable.
I wouldn't worry about the breeding tube at this point, unless it starts to look way out of the norm.
Not sure about the jittering - it might settle down once the fish feels comfortable. Keep an eye out for ich (white spots), and add some salt for good measure.
The faded colors likely indicate that your fish isn't comfortable in its tank yet. The substrate is very light and reflective, which may be contributing to the fish's washed-out appearance. It may also be reacting in a submissive manner to tank mates. Genetics also plays a role in colors, but it is impossible to say how that will play out.
Vieja will tolerate salt. The temperature range you have sounds fine, although it would be best if it remains relatively stable.
I wouldn't worry about the breeding tube at this point, unless it starts to look way out of the norm.
Not sure about the jittering - it might settle down once the fish feels comfortable. Keep an eye out for ich (white spots), and add some salt for good measure.
