The bug

Water bottles, awkward potions, mundane potions and thick potions, along with their projectile variants, all use the exact same color as each other, making them completely indistinguishable from each other without reading their names.

Unlike some recent reports regarding effect potions, the colors are not merely similar, but the exact same (hex #395FCA).

As water bottles and base potions have distinct roles in gameplay, having them be indistinguishable from each other is confusing and counterproductive for everyone.

This issue appears to have been highlighted in MC-260456, a ticket which has recently been fixed. However, this specific problem still remains.

How to fix

This should be a simple fix - these four potions just need to be assigned some different colors from each other:

• Water bottles appear to still be using the pre-1.13 water color. The color water bottles use would preferably be changed to reflect the new default water color: hex #3F76E4
• Awkward potions could be assigned some different color. They could still be kept as a shade of blue - perhaps a darker one to indicate that they're still a base potion with no effects (much like a water bottle), but visually distinct enough as to alleviate confusion.
• Mundane and thick potions could be given a third color to set them apart from water bottles and awkward potions. This could be a third, distinct shade of blue which fits with the theme of base potions being blue while staying easily distinguishable from the other two. They could also be black, indicating a botched experiment which is best off discarded (weakness potions may need to be made slightly lighter in this case).

Further notes

Unrelated to colors, but I'm not sure why thick potions still exist, anyway - they seem to be an odd item carried over from the Beta 1.9 prereleases which are no longer functionally different from mundane potions, so it may be advisable to just remove them and merge them into mundane potions.