Yes and No, Dark discoloration of all the teeth could just be stains from coffee or cigarettes, but if its just on small spots or specific teeth it would probably be a sign of decay.
my best advice is to see a dentist asap, better to get it looked at earlier that later
Cullen's sign
If your betta is showing signs of lethargy, loss of appetite, discoloration, or unusual behavior, it may be a sign that it is unwell and potentially dying. It is important to monitor its condition closely and consider seeking advice from a veterinarian or experienced fish keeper for proper diagnosis and treatment.
Chadwick's sign
yes it is
An eccymotic discoloration over the umbilicus is called a Cullen's sign, which can be a sign of internal bleeding in the abdomen, such as from a ruptured ectopic pregnancy or pancreatitis. It is important to seek immediate medical attention if this sign is noticed.
tooth
A sign in the dark could be a warning or guidance signal, such as a illuminated sign, street sign, or a light indicating directions or information. It helps people navigate or avoid potential dangers in low light conditions.
If it is 6mm or larger in size get it checked out. Discoloration is also a sign.
The sign most associated with the crucifixion is the cross.
Synosis is defined as a discoloration of the skin as well as the mucous membranes. This is a sign that oxygen is in the blood.
dark mark
no it is not ,try going to the dentist so they can take a look at ur tooth bc it may be an infetion in ur gums,or tooth